diff --git a/scripts/modules/blend_render_info.py b/scripts/modules/blend_render_info.py
index 0ba02ab17fc..1d2b60619b1 100755
--- a/scripts/modules/blend_render_info.py
+++ b/scripts/modules/blend_render_info.py
@@ -113,6 +113,13 @@ def _read_blend_rend_chunk_from_file(blendfile, filepath):
 
             scene_name = blendfile.read(64)
             sizeof_data_left -= 64
+            if b'\0' not in scene_name:
+                if sizeof_data_left >= 192:
+                    # Assume new, up to 256 bytes name.
+                    scene_name += blendfile.read(192)
+                    sizeof_data_left -= 192
+            if b'\0' not in scene_name:
+                scene_name = scene_name[:-1] + b'\0'
 
             scene_name = scene_name[:scene_name.index(b'\0')]
             # It's possible old blend files are not UTF8 compliant, use `surrogateescape`.
diff --git a/source/blender/animrig/intern/action_test.cc b/source/blender/animrig/intern/action_test.cc
index e34c3f47f88..d42f7024959 100644
--- a/source/blender/animrig/intern/action_test.cc
+++ b/source/blender/animrig/intern/action_test.cc
@@ -1130,14 +1130,25 @@ TEST_F(ActionLayersTest, conversion_to_layered)
   ASSERT_TRUE(bag->fcurve_array[0]->modifiers.first == nullptr);
   ASSERT_TRUE(bag->fcurve_array[1]->modifiers.first != nullptr);
 
-  Action *long_name_action = BKE_id_new<Action>(
-      bmain, "name_for_an_action_that_is_exactly_64_chars_which_is_MAX_ID_NAME");
+  constexpr char id_name_max[] =
+      "name_for_an_action_that_is_exactly_255_bytes_MAX_ID_NAME-3______"
+      "name_for_an_action_that_is_exactly_255_bytes_MAX_ID_NAME-3______"
+      "name_for_an_action_that_is_exactly_255_bytes_MAX_ID_NAME-3______"
+      "name_for_an_action_that_is_exactly_255_bytes_MAX_ID_NAME-3_____";
+  BLI_STATIC_ASSERT(std::string::traits_type::length(id_name_max) == MAX_ID_NAME - 2 - 1,
+                    "Wrong 'max length' name");
+  Action *long_name_action = BKE_id_new<Action>(bmain, id_name_max);
   action_fcurve_ensure_legacy(bmain, long_name_action, "Long", nullptr, {"location", 0});
+  /* The long name is shortened to make space for "_layered". */
+  constexpr char id_name_max_converted[] =
+      "name_for_an_action_that_is_exactly_255_bytes_MAX_ID_NAME-3______"
+      "name_for_an_action_that_is_exactly_255_bytes_MAX_ID_NAME-3______"
+      "name_for_an_action_that_is_exactly_255_bytes_MAX_ID_NAME-3______"
+      "name_for_an_action_that_is_exactly_255_bytes_MAX_ID_NAM_layered";
+  BLI_STATIC_ASSERT(std::string::traits_type::length(id_name_max_converted) == MAX_ID_NAME - 2 - 1,
+                    "Wrong 'max length' name");
   converted = convert_to_layered_action(*bmain, *long_name_action);
-  /* AC gets added automatically by Blender, the long name is shortened to make space for
-   * "_layered". */
-  EXPECT_STREQ(converted->id.name,
-               "ACname_for_an_action_that_is_exactly_64_chars_which_is_MA_layered");
+  EXPECT_STREQ(BKE_id_name(converted->id), id_name_max_converted);
 }
 
 TEST_F(ActionLayersTest, conversion_to_layered_action_groups)
diff --git a/source/blender/asset_system/AS_asset_library.hh b/source/blender/asset_system/AS_asset_library.hh
index 024da532e83..86be474b0cf 100644
--- a/source/blender/asset_system/AS_asset_library.hh
+++ b/source/blender/asset_system/AS_asset_library.hh
@@ -299,7 +299,7 @@ void AS_asset_library_remap_ids(const blender::bke::id::IDRemapper &mappings);
  * \param r_name: Returns the ID name on success. Optional (passing null is allowed).
  */
 void AS_asset_full_path_explode_from_weak_ref(const AssetWeakReference *asset_reference,
-                                              char r_path_buffer[1090 /* FILE_MAX_LIBEXTRA */],
+                                              char r_path_buffer[1282 /* FILE_MAX_LIBEXTRA */],
                                               char **r_dir,
                                               char **r_group,
                                               char **r_name);
diff --git a/source/blender/asset_system/intern/asset_library.cc b/source/blender/asset_system/intern/asset_library.cc
index de6b2414598..1f73928651d 100644
--- a/source/blender/asset_system/intern/asset_library.cc
+++ b/source/blender/asset_system/intern/asset_library.cc
@@ -103,7 +103,7 @@ void AS_asset_library_remap_ids(const bke::id::IDRemapper &mappings)
 }
 
 void AS_asset_full_path_explode_from_weak_ref(const AssetWeakReference *asset_reference,
-                                              char r_path_buffer[1090 /* FILE_MAX_LIBEXTRA */],
+                                              char r_path_buffer[1282 /* FILE_MAX_LIBEXTRA */],
                                               char **r_dir,
                                               char **r_group,
                                               char **r_name)
@@ -129,7 +129,7 @@ void AS_asset_full_path_explode_from_weak_ref(const AssetWeakReference *asset_re
   BLI_assert(!exploded->group_component.is_empty());
   BLI_assert(!exploded->name_component.is_empty());
 
-  BLI_strncpy(r_path_buffer, exploded->full_path->c_str(), 1090 /* #FILE_MAX_LIBEXTRA. */);
+  BLI_strncpy(r_path_buffer, exploded->full_path->c_str(), 1282 /* #FILE_MAX_LIBEXTRA. */);
 
   if (!exploded->dir_component.is_empty()) {
     r_path_buffer[exploded->dir_component.size()] = '\0';
diff --git a/source/blender/asset_system/intern/asset_representation.cc b/source/blender/asset_system/intern/asset_representation.cc
index d130e856cbd..9e2f6d60014 100644
--- a/source/blender/asset_system/intern/asset_representation.cc
+++ b/source/blender/asset_system/intern/asset_representation.cc
@@ -132,7 +132,7 @@ std::string AssetRepresentation::full_library_path() const
 {
   std::string asset_path = full_path();
 
-  char blend_path[/*FILE_MAX_LIBEXTRA*/ 1090];
+  char blend_path[/*FILE_MAX_LIBEXTRA*/ 1282];
   if (!BKE_blendfile_library_path_explode(asset_path.c_str(), blend_path, nullptr, nullptr)) {
     return {};
   }
diff --git a/source/blender/blenkernel/BKE_blender_version.h b/source/blender/blenkernel/BKE_blender_version.h
index aadaf8cc32c..340b90b7cdd 100644
--- a/source/blender/blenkernel/BKE_blender_version.h
+++ b/source/blender/blenkernel/BKE_blender_version.h
@@ -27,7 +27,7 @@
 
 /* Blender file format version. */
 #define BLENDER_FILE_VERSION BLENDER_VERSION
-#define BLENDER_FILE_SUBVERSION 21
+#define BLENDER_FILE_SUBVERSION 22
 
 /* Minimum Blender version that supports reading file written with the current
  * version. Older Blender versions will test this and cancel loading the file, showing a warning to
diff --git a/source/blender/blenkernel/BKE_lib_id.hh b/source/blender/blenkernel/BKE_lib_id.hh
index f6303f46d65..0fe6e22cec8 100644
--- a/source/blender/blenkernel/BKE_lib_id.hh
+++ b/source/blender/blenkernel/BKE_lib_id.hh
@@ -788,8 +788,8 @@ void BKE_main_lib_objects_recalc_all(Main *bmain);
  */
 void BKE_main_id_repair_duplicate_names_listbase(Main *bmain, ListBase *lb);
 
-#define MAX_ID_FULL_NAME (64 + 64 + 3 + 1)         /* 64 is MAX_ID_NAME - 2 */
-#define MAX_ID_FULL_NAME_UI (MAX_ID_FULL_NAME + 3) /* Adds `keycode` two letters at beginning. */
+#define MAX_ID_FULL_NAME (256 + 256 + 3 + 1)       /* 256 is MAX_ID_NAME - 2 */
+#define MAX_ID_FULL_NAME_UI (MAX_ID_FULL_NAME + 3) /* Adds 'keycode' two letters at beginning. */
 /**
  * Generate full name of the data-block (without ID code, but with library if any).
  *
diff --git a/source/blender/blenkernel/intern/asset_edit.cc b/source/blender/blenkernel/intern/asset_edit.cc
index 001d7f9e6bb..90ad2c799a1 100644
--- a/source/blender/blenkernel/intern/asset_edit.cc
+++ b/source/blender/blenkernel/intern/asset_edit.cc
@@ -125,6 +125,11 @@ static std::string asset_blendfile_path_for_save(const bUserAssetLibrary &user_l
               std::min(sizeof(base_name_filesafe), size_t(base_name.size() + 1)));
   BLI_path_make_safe_filename(base_name_filesafe);
 
+  /* FIXME: MAX_ID_NAME & FILE_MAXFILE
+   *
+   * This already does not respect the FILE_MAXFILE max length of filenames for the final filepath
+   * it seems?
+   */
   {
     const std::string filepath = root_path + SEP + base_name_filesafe + BLENDER_ASSET_FILE_SUFFIX;
     if (!BLI_is_file(filepath.c_str())) {
diff --git a/source/blender/blenkernel/intern/lib_id_test.cc b/source/blender/blenkernel/intern/lib_id_test.cc
index dd792c9b2ba..f139d64a06b 100644
--- a/source/blender/blenkernel/intern/lib_id_test.cc
+++ b/source/blender/blenkernel/intern/lib_id_test.cc
@@ -14,6 +14,8 @@
 
 #include "DNA_ID.h"
 
+#include <string>
+
 namespace blender::bke::tests {
 
 struct LibIDMainSortTestContext {
@@ -163,13 +165,27 @@ TEST(lib_id_main_unique_name, local_ids_rename_existing_never)
   STRNCPY(future_name, "OB_BBBB");
   EXPECT_FALSE(BKE_main_namemap_get_unique_name(*ctx.bmain, *id_c, future_name));
   EXPECT_STREQ(future_name, "OB_BBBB");
+  constexpr char long_name[] =
+      "OB_BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB"
+      "BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB"
+      "BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB"
+      "BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB";
+  BLI_STATIC_ASSERT(std::string::traits_type::length(long_name) == MAX_ID_NAME - 2 - 1,
+                    "Wrong 'max length' name");
+  constexpr char long_name_shorten[] =
+      "OB_BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB"
+      "BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB"
+      "BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB"
+      "BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB";
+  BLI_STATIC_ASSERT(std::string::traits_type::length(long_name_shorten) == MAX_ID_NAME - 2 - 2,
+                    "Wrong 'max length' name");
   /* Name too long, needs to be truncated. */
-  STRNCPY(future_name, "OB_BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB");
+  STRNCPY(future_name, long_name);
   change_name(ctx.bmain, id_a, future_name, IDNewNameMode::RenameExistingNever);
   EXPECT_STREQ(id_a->name + 2, future_name);
-  EXPECT_STREQ(future_name, "OB_BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB");
+  EXPECT_STREQ(future_name, long_name);
   EXPECT_TRUE(BKE_main_namemap_get_unique_name(*ctx.bmain, *id_c, future_name));
-  EXPECT_STREQ(future_name, "OB_BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB");
+  EXPECT_STREQ(future_name, long_name_shorten);
 }
 
 TEST(lib_id_main_unique_name, local_ids_rename_existing_always)
@@ -303,7 +319,7 @@ TEST(lib_id_main_unique_name, linked_ids_1)
 static void change_name_global(Main *bmain, ID *id, const char *name)
 {
   BKE_main_namemap_remove_id(*bmain, *id);
-  BLI_strncpy(id->name + 2, name, MAX_NAME);
+  BLI_strncpy(id->name + 2, name, MAX_ID_NAME - 2);
 
   BKE_main_global_namemap_get_unique_name(*bmain, *id, id->name + 2);
 
@@ -415,17 +431,45 @@ TEST(lib_id_main_unique_name, ids_sorted_by_default_with_libraries)
 TEST(lib_id_main_unique_name, name_too_long_handling)
 {
   LibIDMainSortTestContext ctx;
-  const char *name_a = "Long_Name_That_Does_Not_Fit_Into_Max_Name_Limit_And_Should_Get_Truncated";
-  const char *name_b = "Another_Long_Name_That_Does_Not_Fit_And_Has_A_Number_Suffix.123456";
-  const char *name_c = "Name_That_Has_Too_Long_Number_Suffix.1234567890";
+  constexpr char name_a[] =
+      "Long_Name_That_Does_Not_Fit_Into_Max_Name_Limit_And_Should_Get_Truncated_"
+      "Long_Name_That_Does_Not_Fit_Into_Max_Name_Limit_And_Should_Get_Truncated_"
+      "Long_Name_That_Does_Not_Fit_Into_Max_Name_Limit_And_Should_Get_Truncated_"
+      "Long_Name_That_Does_Not_Fit_Into_Max_Name_Limit_And_Should_Get_Truncated";
+  BLI_STATIC_ASSERT(std::string::traits_type::length(name_a) > MAX_ID_NAME - 2,
+                    "Wrong 'max length' name");
+  constexpr char name_a_shorten[] =
+      "Long_Name_That_Does_Not_Fit_Into_Max_Name_Limit_And_Should_Get_Truncated_"
+      "Long_Name_That_Does_Not_Fit_Into_Max_Name_Limit_And_Should_Get_Truncated_"
+      "Long_Name_That_Does_Not_Fit_Into_Max_Name_Limit_And_Should_Get_Truncated_"
+      "Long_Name_That_Does_Not_Fit_Into_Max";
+  BLI_STATIC_ASSERT(std::string::traits_type::length(name_a_shorten) == MAX_ID_NAME - 2 - 1,
+                    "Wrong 'max length' name");
+  constexpr char name_b[] =
+      "Another_Long_Name_That_Does_Not_Fit_And_Has_A_Number_Suffix_____"
+      "Another_Long_Name_That_Does_Not_Fit_And_Has_A_Number_Suffix_____"
+      "Another_Long_Name_That_Does_Not_Fit_And_Has_A_Number_Suffix_____"
+      "Another_Long_Name_That_Does_Not_Fit_And_Has_A_Number_Suffix.123456";
+  BLI_STATIC_ASSERT(std::string::traits_type::length(name_b) > MAX_ID_NAME - 2,
+                    "Wrong 'max length' name");
+  constexpr char name_b_shorten[] =
+      "Another_Long_Name_That_Does_Not_Fit_And_Has_A_Number_Suffix_____"
+      "Another_Long_Name_That_Does_Not_Fit_And_Has_A_Number_Suffix_____"
+      "Another_Long_Name_That_Does_Not_Fit_And_Has_A_Number_Suffix_____"
+      "Another_Long_Name_That_Does_Not_Fit_And_Has_A_Number_Suffix.123";
+  BLI_STATIC_ASSERT(std::string::traits_type::length(name_b_shorten) == MAX_ID_NAME - 2 - 1,
+                    "Wrong 'max length' name");
+  constexpr char name_c[] = "Name_That_Has_Too_Long_Number_Suffix.1234567890";
+  BLI_STATIC_ASSERT(std::string::traits_type::length(name_c) < MAX_ID_NAME - 2,
+                    "Wrong 'max length' name");
 
   ID *id_a = static_cast<ID *>(BKE_id_new(ctx.bmain, ID_OB, name_a));
   ID *id_b = static_cast<ID *>(BKE_id_new(ctx.bmain, ID_OB, name_b));
   ID *id_c = static_cast<ID *>(BKE_id_new(ctx.bmain, ID_OB, name_c));
 
-  EXPECT_STREQ(id_a->name + 2, "Long_Name_That_Does_Not_Fit_Into_Max_Name_Limit_And_Should_Get_");
-  EXPECT_STREQ(id_b->name + 2, "Another_Long_Name_That_Does_Not_Fit_And_Has_A_Number_Suffix.123");
-  EXPECT_STREQ(id_c->name + 2, "Name_That_Has_Too_Long_Number_Suffix.1234567890"); /* Unchanged */
+  EXPECT_STREQ(BKE_id_name(*id_a), name_a_shorten);
+  EXPECT_STREQ(BKE_id_name(*id_b), name_b_shorten);
+  EXPECT_STREQ(BKE_id_name(*id_c), name_c); /* Unchanged */
 
   EXPECT_TRUE(BKE_main_namemap_validate(*ctx.bmain));
 
diff --git a/source/blender/blenlib/intern/path_utils.cc b/source/blender/blenlib/intern/path_utils.cc
index bcedf44c35b..bd5207e37af 100644
--- a/source/blender/blenlib/intern/path_utils.cc
+++ b/source/blender/blenlib/intern/path_utils.cc
@@ -133,6 +133,12 @@ void BLI_path_sequence_encode(char *path,
 {
   BLI_string_debug_size(path, path_maxncpy);
 
+  /* FIXME: MAX_ID_NAME & FILE_MAXFILE
+   *
+   * As this function directly works on a full file path (typically a FILE_MAX long char buffer),
+   * and does not perform any check on the filename part of the path, it can easily generate final
+   * paths containing a filename longer than the max supported length (FILE_MAXFILE).
+   */
   BLI_snprintf(path, path_maxncpy, "%s%.*d%s", head, numlen, std::max(0, pic), tail);
 }
 
diff --git a/source/blender/editors/include/UI_interface_types.hh b/source/blender/editors/include/UI_interface_types.hh
index 9ce071e00b4..f7bac69f166 100644
--- a/source/blender/editors/include/UI_interface_types.hh
+++ b/source/blender/editors/include/UI_interface_types.hh
@@ -12,8 +12,8 @@ struct bContext;
 struct uiLayout;
 
 /* names */
-#define UI_MAX_DRAW_STR 400
-#define UI_MAX_NAME_STR 128
+#define UI_MAX_DRAW_STR 550
+#define UI_MAX_NAME_STR 256
 #define UI_MAX_SHORTCUT_STR 64
 
 /* Menu Callbacks */
diff --git a/source/blender/editors/sculpt_paint/brush_asset_ops.cc b/source/blender/editors/sculpt_paint/brush_asset_ops.cc
index 7086a6a34d1..e9ba3db327e 100644
--- a/source/blender/editors/sculpt_paint/brush_asset_ops.cc
+++ b/source/blender/editors/sculpt_paint/brush_asset_ops.cc
@@ -153,6 +153,12 @@ static wmOperatorStatus brush_asset_save_as_exec(bContext *C, wmOperator *op)
 
   /* Determine file path to save to. */
   PropertyRNA *name_prop = RNA_struct_find_property(op->ptr, "name");
+  /* FIXME: MAX_ID_NAME & FILE_MAXFILE
+   *
+   * This `name` should be `MAX_ID_NAME - 2` long.
+   *
+   * This name might also be used as filename for the saved asset, thus hitting the size issue
+   * between ID names and file names (FILE_MAXFILE). */
   char name[MAX_NAME] = "";
   if (RNA_property_is_set(op->ptr, name_prop)) {
     RNA_property_string_get(op->ptr, name_prop, name);
diff --git a/source/blender/editors/space_file/filelist.hh b/source/blender/editors/space_file/filelist.hh
index 8f03d7f4239..b02b1ed2bfc 100644
--- a/source/blender/editors/space_file/filelist.hh
+++ b/source/blender/editors/space_file/filelist.hh
@@ -82,7 +82,7 @@ void filelist_init_icons();
 void filelist_free_icons();
 void filelist_file_get_full_path(const FileList *filelist,
                                  const FileDirEntry *file,
-                                 char r_filepath[/*FILE_MAX_LIBEXTRA*/ 1090]);
+                                 char r_filepath[/*FILE_MAX_LIBEXTRA*/ 1282]);
 bool filelist_file_is_preview_pending(const FileList *filelist, const FileDirEntry *file);
 /**
  * \return True if a new preview request was pushed, false otherwise (e.g. because the preview is
@@ -121,7 +121,7 @@ bool filelist_is_dir(const FileList *filelist, const char *path);
 /**
  * May modify in place given `dirpath`, which is expected to be #FILE_MAX_LIBEXTRA length.
  */
-void filelist_setdir(FileList *filelist, char dirpath[/*FILE_MAX_LIBEXTRA*/ 1090]);
+void filelist_setdir(FileList *filelist, char dirpath[/*FILE_MAX_LIBEXTRA*/ 1282]);
 
 /**
  * Limited version of full update done by space_file's file_refresh(),
diff --git a/source/blender/editors/space_view3d/view3d_draw.cc b/source/blender/editors/space_view3d/view3d_draw.cc
index f81f6dded59..8b70d7571e6 100644
--- a/source/blender/editors/space_view3d/view3d_draw.cc
+++ b/source/blender/editors/space_view3d/view3d_draw.cc
@@ -1364,6 +1364,17 @@ static void draw_selected_name(
     char frame[16];
   } info_buffers;
 
+  /* Info can contain:
+   * - 1 frame number `(7 + 2)`.
+   * - 1 collection name `(MAX_ID_NAME - 2 + 3)`.
+   * - 1 object name `(MAX_ID_NAME - 2)`.
+   * - 1 object data name `(MAX_ID_NAME - 2)`.
+   * - 2 non-ID data names (bones, shapekeys...) `(MAX_NAME * 2)`.
+   * - 2 BREAD_CRUMB_SEPARATOR(s) `(6)`.
+   * - 1 SHAPE_KEY_PINNED marker and a trailing '\0' `(9+1)` - translated, so give some room!
+   * - 1 marker name `(MAX_NAME + 3)`.
+   */
+
   SNPRINTF(info_buffers.frame, "(%d)", cfra);
   info_array[i++] = info_buffers.frame;
 
@@ -1377,15 +1388,6 @@ static void draw_selected_name(
     }
   }
 
-  /* Info can contain:
-   * - A frame `(7 + 2)`.
-   * - A collection name `(MAX_NAME + 3)`.
-   * - 3 object names `(MAX_NAME)`.
-   * - 2 BREAD_CRUMB_SEPARATOR(s) `(6)`.
-   * - A SHAPE_KEY_PINNED marker and a trailing '\0' `(9+1)` - translated, so give some room!
-   * - A marker name `(MAX_NAME + 3)`.
-   */
-
   /* get name of marker on current frame (if available) */
   const char *markern = BKE_scene_find_marker_name(scene, cfra);
 
@@ -1477,9 +1479,12 @@ static void draw_selected_name(
   }
 
   BLI_assert(i < int(ARRAY_SIZE(info_array)));
-  char info[300];
-  /* It's expected there will be enough room for the buffer (if not, increase it). */
+
+  char info[MAX_ID_NAME * 4];
+  /* It's expected there will be enough room for the whole string in the the buffer. If not,
+   * increase it. */
   BLI_assert(BLI_string_len_array(info_array, i) < sizeof(info));
+
   BLI_string_join_array(info, sizeof(info), info_array, i);
 
   *yoffset -= VIEW3D_OVERLAY_LINEHEIGHT;
diff --git a/source/blender/makesdna/DNA_ID.h b/source/blender/makesdna/DNA_ID.h
index 2bd7af4709b..f5baf354d13 100644
--- a/source/blender/makesdna/DNA_ID.h
+++ b/source/blender/makesdna/DNA_ID.h
@@ -359,8 +359,8 @@ enum {
  * provides a common handle to place all data in double-linked lists.
  */
 
-/* 2 characters for ID code and 64 for actual name */
-#define MAX_ID_NAME 66
+/* 2 characters for ID code and 256 for actual name */
+#define MAX_ID_NAME 258
 
 /** #ID_Runtime_Remap.status */
 enum {
@@ -412,7 +412,15 @@ typedef struct ID {
   /** If the ID is an asset, this pointer is set. Owning pointer. */
   struct AssetMetaData *asset_data;
 
-  char name[/*MAX_ID_NAME*/ 66];
+  /**
+   * Main identifier for this data-block. Must be unique within the ID name-space (defined by its
+   * type, and owning #Library).
+   *
+   * The first two bytes are always the #ID_Type code of the data-block's type.
+   *
+   * One critical usage is to reference external linked data. */
+  char name[/*MAX_ID_NAME*/ 258];
+
   /**
    * ID_FLAG_... flags report on status of the data-block this ID belongs to
    * (persistent, saved to and read from .blend).
@@ -531,7 +539,7 @@ typedef struct LibraryWeakReference {
   char library_filepath[/*FILE_MAX*/ 1024];
 
   /** May be different from the current local ID name. */
-  char library_id_name[/*MAX_ID_NAME*/ 66];
+  char library_id_name[/*MAX_ID_NAME*/ 258];
 
   char _pad[2];
 } LibraryWeakReference;
diff --git a/source/blender/makesdna/DNA_action_types.h b/source/blender/makesdna/DNA_action_types.h
index 881ca18dd99..6ea580eb95c 100644
--- a/source/blender/makesdna/DNA_action_types.h
+++ b/source/blender/makesdna/DNA_action_types.h
@@ -1184,7 +1184,7 @@ typedef struct ActionSlot {
    *
    * \see #AnimData::slot_name
    */
-  char identifier[/*MAX_ID_NAME*/ 66];
+  char identifier[/*MAX_ID_NAME*/ 258];
 
   /**
    * Type of ID-block that this slot is intended for.
diff --git a/source/blender/makesdna/DNA_anim_types.h b/source/blender/makesdna/DNA_anim_types.h
index 44a9e3c7727..85771d64254 100644
--- a/source/blender/makesdna/DNA_anim_types.h
+++ b/source/blender/makesdna/DNA_anim_types.h
@@ -441,7 +441,7 @@ typedef struct NlaStrip {
    * \note Most code should not write to this field directly, but use functions from
    * `blender::animrig::nla` instead, see ANIM_nla.hh.
    */
-  char last_slot_identifier[66]; /* MAX_ID_NAME */
+  char last_slot_identifier[/* MAX_ID_NAME */ 258];
   char _pad0[2];
 
   /** F-Curves for controlling this strip's influence and timing */ /* TODO: move out? */
@@ -677,7 +677,7 @@ typedef struct AnimData {
    *
    * \see #ActionSlot::name
    */
-  char last_slot_identifier[66]; /* MAX_ID_NAME */
+  char last_slot_identifier[/* MAX_ID_NAME */ 258];
   uint8_t _pad0[2];
 
   /**
@@ -686,7 +686,7 @@ typedef struct AnimData {
    */
   bAction *tmpact;
   int32_t tmp_slot_handle;
-  char tmp_last_slot_identifier[66]; /* MAX_ID_NAME */
+  char tmp_last_slot_identifier[/* MAX_ID_NAME */ 258];
   uint8_t _pad1[2];
 
   /* nla-tracks */
diff --git a/source/blender/makesdna/DNA_constraint_types.h b/source/blender/makesdna/DNA_constraint_types.h
index 2446df97652..907b0fdf7c8 100644
--- a/source/blender/makesdna/DNA_constraint_types.h
+++ b/source/blender/makesdna/DNA_constraint_types.h
@@ -303,7 +303,7 @@ typedef struct bActionConstraint {
   float eval_time; /* Only used when flag ACTCON_USE_EVAL_TIME is set. */
   struct bAction *act;
   int32_t action_slot_handle;
-  char last_slot_identifier[/*MAX_ID_NAME*/ 66];
+  char last_slot_identifier[/*MAX_ID_NAME*/ 258];
   char _pad1[2];
   char subtarget[/*MAX_NAME*/ 64];
 } bActionConstraint;
diff --git a/source/blender/makesdna/DNA_space_types.h b/source/blender/makesdna/DNA_space_types.h
index 5655a8f352e..67ab1fce395 100644
--- a/source/blender/makesdna/DNA_space_types.h
+++ b/source/blender/makesdna/DNA_space_types.h
@@ -396,10 +396,10 @@ typedef struct FileSelectParams {
   /**
    * Directory.
    *
-   * \note #FILE_MAX_LIBEXTRA == `1024 + 66`, this is for extreme case when 1023 length path
+   * \note #FILE_MAX_LIBEXTRA == `1024 + 258`, this is for extreme case when 1023 length path
    * needs to be linked in, where `foo.blend/Armature` need adding.
    */
-  char dir[/*FILE_MAX_LIBEXTRA*/ 1090];
+  char dir[/*FILE_MAX_LIBEXTRA*/ 1282];
   char file[/*FILE_MAXFILE*/ 256];
 
   char renamefile[/*FILE_MAXFILE*/ 256];
diff --git a/source/blender/render/intern/render_result.cc b/source/blender/render/intern/render_result.cc
index 8f3651c489d..8e314cdd37b 100644
--- a/source/blender/render/intern/render_result.cc
+++ b/source/blender/render/intern/render_result.cc
@@ -1034,6 +1034,11 @@ static void render_result_exr_file_cache_path(Scene *sce,
     root = root_buf;
   }
 
+  /* FIXME: MAX_ID_NAME & FILE_MAXFILE
+   *
+   * If #filename is already long (it is initialized from the blend-file name itself), adding the
+   * scene name can cause the file name to be truncated.
+   */
   SNPRINTF(filename_full, "cached_RR_%s_%s_%s.exr", filename, sce->id.name + 2, path_hexdigest);
 
   BLI_path_join(r_path, FILE_CACHE_MAX, root, filename_full);
diff --git a/tests/files/io_tests/fbx/max2025-longnames.fbx b/tests/files/io_tests/fbx/max2025-longnames.fbx
index 7e82c836dfc..d7930d34da4 100644
--- a/tests/files/io_tests/fbx/max2025-longnames.fbx
+++ b/tests/files/io_tests/fbx/max2025-longnames.fbx
@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:8ac81b86b89910406e919dc51fe77d44cf27e0aa581695c8a3268f14b219caf0
-size 74896
+oid sha256:971ef1c87a73a6abceff2aff78731d75bc91b0e96cb9fe22f3925dcf0fb31975
+size 71452
diff --git a/tests/files/io_tests/fbx/reference/max2025-longnames.txt b/tests/files/io_tests/fbx/reference/max2025-longnames.txt
index a9e0d7121ac..4b378f13b9f 100644
--- a/tests/files/io_tests/fbx/reference/max2025-longnames.txt
+++ b/tests/files/io_tests/fbx/reference/max2025-longnames.txt
@@ -135,7 +135,7 @@
       -0.210 0.000 0.978 0.000
     - props: int:MaxHandle=3
   - anim act:Take 001 slot:OBArmature blend:REPLACE drivers:0
-- Obj 'Box_With_A_Long_Name_To_Test_Importer_Handling_Of_Names_That_A' MESH data:'Mesh.002' par:'Armature'
+- Obj 'Box_With_A_Long_Name_To_Test_Importer_Handling_Of_Names_That_Are_Too_Long_To_Fit_Box_With_A_Long_Name_To_Test_Importer_Handling_Of_Names_That_Are_Too_Long_To_Fit_Box_With_A_Long_Name_To_Test_Importer_Handling_Of_Names_That_Are_Too_Long_To_Fit_Box_With_A_' MESH data:'Mesh.002' par:'Armature'
   - pos 0.679, 0.000, 15.811
   - rot -1.571, 0.000, 0.000 (XYZ)
   - scl 1.000, 1.000, 1.000
@@ -144,7 +144,7 @@
   - 1 modifiers
     - ARMATURE 'Armature'
   - props: int:MaxHandle=10
-- Obj 'Box_With_A_Long_Name_To_Test_Importer_Handling_Of_Names_That_Ar' MESH data:'Mesh' par:'Armature'
+- Obj 'Box_With_A_Long_Name_To_Test_Importer_Handling_Of_Names_That_Are_Too_Long_To_Fit_Box_With_A_Long_Name_To_Test_Importer_Handling_Of_Names_That_Are_Too_Long_To_Fit_Box_With_A_Long_Name_To_Test_Importer_Handling_Of_Names_That_Are_Too_Long_To_Fit_Box_With_A_L' MESH data:'Mesh' par:'Armature'
   - pos 0.679, 0.000, -0.945
   - rot -1.571, 0.000, 0.000 (XYZ)
   - scl 1.000, 1.000, 1.000
@@ -153,17 +153,17 @@
   - 1 modifiers
     - ARMATURE 'Armature'
   - props: int:MaxHandle=2
-- Obj 'Box_Yellow_That_Is_Animated_And_Also_With_A_Long_Name_Let_Us_Se' MESH data:'Mesh.003'
+- Obj 'Box_Yellow_That_Is_Animated_And_Also_With_A_Long_Name_Let_Us_See_What_Happens_Here_Box_Yellow_That_Is_Animated_And_Also_With_A_Long_Name_Let_Us_See_What_Happens_Here_Box_Yellow_That_Is_Animated_And_Also_With_A_Long_Name_Let_Us_See_What_Happens_Here_Box_Ye' MESH data:'Mesh.003'
   - pos -0.261, -0.829, 0.000
   - rot 0.000, 0.000, 0.000 (XYZ)
   - scl 0.025, 0.025, 0.025
-  - anim act:Take 001 slot:OBBox_Yellow_That_Is_Animated_And_Also_With_A_Long_Name_Let_Us_Se blend:REPLACE drivers:0
+  - anim act:Take 001 slot:OBBox_Yellow_That_Is_Animated_And_Also_With_A_Long_Name_Let_Us_See_What_Happens_Here_Box_Yellow_That_Is_Animated_And_Also_With_A_Long_Name_Let_Us_See_What_Happens_Here_Box_Yellow_That_Is_Animated_And_Also_With_A_Long_Name_Let_Us_See_What_Happens_Here_Box_Ye blend:REPLACE drivers:0
   - props: int:MaxHandle=14
-- Obj 'Point_Light_Object_Color_Blue_Light_Color_Animated_With_A_Long_' LIGHT data:'Light'
+- Obj 'Point_Light_Object_Color_Blue_Light_Color_Animated_With_A_Long_Name_Here_Point_Light_Object_Color_Blue_Light_Color_Animated_With_A_Long_Name_Here_Point_Light_Object_Color_Blue_Light_Color_Animated_With_A_Long_Name_Here_Point_Light_Object_Color_Blue_Light_' LIGHT data:'Light'
   - pos 0.567, -0.741, 0.000
   - rot 0.000, 0.000, 0.000 (XYZ)
   - scl 0.025, 0.025, 0.025
-  - anim act:Take 001 slot:OBPoint_Light_Object_Color_Blue_Light_Color_Animated_With_A_Long_ blend:REPLACE drivers:0
+  - anim act:Take 001 slot:OBPoint_Light_Object_Color_Blue_Light_Color_Animated_With_A_Long_Name_Here_Point_Light_Object_Color_Blue_Light_Color_Animated_With_A_Long_Name_Here_Point_Light_Object_Color_Blue_Light_Color_Animated_With_A_Long_Name_Here_Point_Light_Object_Color_Blue_Light_ blend:REPLACE drivers:0
   - props: int:MaxHandle=15
 - Obj 'Sphere_Parented_To_Bone' MESH data:'Mesh.001' par:'Armature' par_type:BONE par_bone:'Likewise_Here_Is_A_Bone_With_A_Long_Name_To_See_What_Happen.002'
   - pos 6.099, -21.143, 2.790
@@ -224,7 +224,7 @@
   - fcu 'pose.bones["Likewise_Here_Is_A_Bone_With_A_Long_Name_To_See_What_Happen.003"].rotation_quaternion[1]' smooth:CONT_ACCEL extra:CONSTANT keyframes:2 grp:'Likewise_Here_Is_A_Bone_With_A_Long_Name_To_See_What_Happen.003'
     - (1.000, 0.000) lh:(-0.667, 0.000 AUTO_CLAMPED) rh:(2.667, 0.000 AUTO_CLAMPED)
     - (6.000, 0.000) lh:(4.333, 0.000 AUTO_CLAMPED) rh:(7.667, 0.000 AUTO_CLAMPED)
- - Channelbag slot 'OBBox_Yellow_That_Is_Animated_And_Also_With_A_Long_Name_Let_Us_Se' curves:9
+ - Channelbag slot 'OBBox_Yellow_That_Is_Animated_And_Also_With_A_Long_Name_Let_Us_See_What_Happens_Here_Box_Yellow_That_Is_Animated_And_Also_With_A_Long_Name_Let_Us_See_What_Happens_Here_Box_Yellow_That_Is_Animated_And_Also_With_A_Long_Name_Let_Us_See_What_Happens_Here_Box_Ye' curves:9
   - fcu 'location[0]' smooth:CONT_ACCEL extra:CONSTANT keyframes:2 grp:'Box_Yellow_That_Is_Animated_And_Also_With_A_Long_Name_Let_Us_Se'
     - (1.000, -0.261) lh:(0.000, -0.261 AUTO_CLAMPED) rh:(2.000, -0.261 AUTO_CLAMPED)
     - (4.000, 0.211) lh:(3.000, 0.211 AUTO_CLAMPED) rh:(5.000, 0.211 AUTO_CLAMPED)
@@ -252,7 +252,7 @@
   - fcu 'scale[2]' smooth:CONT_ACCEL extra:CONSTANT keyframes:2 grp:'Box_Yellow_That_Is_Animated_And_Also_With_A_Long_Name_Let_Us_Se'
     - (1.000, 0.025) lh:(0.000, 0.025 AUTO_CLAMPED) rh:(2.000, 0.025 AUTO_CLAMPED)
     - (4.000, 0.025) lh:(3.000, 0.025 AUTO_CLAMPED) rh:(5.000, 0.025 AUTO_CLAMPED)
- - Channelbag slot 'OBPoint_Light_Object_Color_Blue_Light_Color_Animated_With_A_Long_' curves:9
+ - Channelbag slot 'OBPoint_Light_Object_Color_Blue_Light_Color_Animated_With_A_Long_Name_Here_Point_Light_Object_Color_Blue_Light_Color_Animated_With_A_Long_Name_Here_Point_Light_Object_Color_Blue_Light_Color_Animated_With_A_Long_Name_Here_Point_Light_Object_Color_Blue_Light_' curves:9
   - fcu 'location[0]' smooth:CONT_ACCEL extra:CONSTANT keyframes:2 grp:'Point_Light_Object_Color_Blue_Light_Color_Animated_With_A_Long_'
     - (1.000, 0.567) lh:(-0.667, 0.567 AUTO_CLAMPED) rh:(2.667, 0.567 AUTO_CLAMPED)
     - (6.000, 1.148) lh:(4.333, 1.148 AUTO_CLAMPED) rh:(7.667, 1.148 AUTO_CLAMPED)
diff --git a/tests/files/io_tests/obj/invalid_syntax.obj b/tests/files/io_tests/obj/invalid_syntax.obj
index 8b70f6b5586..d6cdb2b89e0 100644
--- a/tests/files/io_tests/obj/invalid_syntax.obj
+++ b/tests/files/io_tests/obj/invalid_syntax.obj
@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:556b5e37a5e2f3c81e7ec846ab33a639d18cde361d21a16183188c1dd4f347fe
-size 762
+oid sha256:37d58400e2e8259deeaa95dc0dad5c9f99bf3a01deeb705f362649bd9193ac33
+size 1020
diff --git a/tests/files/io_tests/obj/reference/invalid_syntax.txt b/tests/files/io_tests/obj/reference/invalid_syntax.txt
index e8a114baa6c..e6c5dbc4303 100644
--- a/tests/files/io_tests/obj/reference/invalid_syntax.txt
+++ b/tests/files/io_tests/obj/reference/invalid_syntax.txt
@@ -1,5 +1,5 @@
 ==== Meshes: 1
-- Mesh 'ObjectWithAReallyLongNameToCheckHowImportHandlesNamesThatAreLon' vtx:3 face:1 loop:3 edge:3
+- Mesh 'ObjectWithAReallyLongNameToCheckHowImportHandlesNamesThatAreLongerThanBlenderCanHandleObjectWithAReallyLongNameToCheckHowImportHandlesNamesThatAreLongerThanBlenderCanHandleObjectWithAReallyLongNameToCheckHowImportHandlesNamesThatAreLongerThanBlenderCanHan' vtx:3 face:1 loop:3 edge:3
     - 0 1 2 
     - 0/2 0/1 1/2 
   - attr 'position' FLOAT_VECTOR POINT
@@ -22,7 +22,7 @@
     - (1.000, 0.750)
 
 ==== Objects: 1
-- Obj 'ObjectWithAReallyLongNameToCheckHowImportHandlesNamesThatAreLon' MESH data:'ObjectWithAReallyLongNameToCheckHowImportHandlesNamesThatAreLon'
+- Obj 'ObjectWithAReallyLongNameToCheckHowImportHandlesNamesThatAreLongerThanBlenderCanHandleObjectWithAReallyLongNameToCheckHowImportHandlesNamesThatAreLongerThanBlenderCanHandleObjectWithAReallyLongNameToCheckHowImportHandlesNamesThatAreLongerThanBlenderCanHan' MESH data:'ObjectWithAReallyLongNameToCheckHowImportHandlesNamesThatAreLongerThanBlenderCanHandleObjectWithAReallyLongNameToCheckHowImportHandlesNamesThatAreLongerThanBlenderCanHandleObjectWithAReallyLongNameToCheckHowImportHandlesNamesThatAreLongerThanBlenderCanHan'
   - pos 0.000, 0.000, 0.000
   - rot 1.571, 0.000, 0.000 (XYZ)
   - scl 1.000, 1.000, 1.000
diff --git a/tests/python/bl_animation_action.py b/tests/python/bl_animation_action.py
index 04b583e057d..51adfa21e37 100644
--- a/tests/python/bl_animation_action.py
+++ b/tests/python/bl_animation_action.py
@@ -68,24 +68,36 @@ class ActionSlotCreationTest(unittest.TestCase):
             self.action.slots.new('UNSPECIFIED', "Bob")
 
     def test_long_identifier(self):
-        # Test a 65-character identifier, using a 63-character name. This is the
-        # maximum length allowed (the DNA field is MAX_ID_NAME=66 long, which
+        # Test a 257-character identifier, using a 255-character name. This is the
+        # maximum length allowed (the DNA field is MAX_ID_NAME=258 long, which
         # includes the trailing zero byte).
-        long_but_ok_name = "This name is so long! It might look long, but it is just right!"
+        long_but_ok_name = (
+            "This name is so long! It might look long, but it is just right! "
+            "This name is so long! It might look long, but it is just right! "
+            "This name is so long! It might look long, but it is just right! "
+            "This name is so long! It might look long, but it is just right!"
+        )
+        assert (len(long_but_ok_name) == 255)
         slot_ok = self.action.slots.new('OBJECT', long_but_ok_name)
         self.assertEqual(long_but_ok_name, slot_ok.name_display, "this name should fit")
         self.assertEqual('OB' + long_but_ok_name, slot_ok.identifier, "this identifier should fit")
 
         # Test one character more.
-        too_long_name = "This name is so long! It might look long, and that it is indeed."
-        too_long_name_truncated = too_long_name[:63]
+        too_long_name = (
+            "This name is so long! It might look long, and that it is indeed."
+            "This name is so long! It might look long, and that it is indeed."
+            "This name is so long! It might look long, and that it is indeed."
+            "This name is so long! It might look long, and that it is indeed."
+        )
+        assert (len(too_long_name) == 256)
+        too_long_name_truncated = too_long_name[:255]
         slot_long = self.action.slots.new('OBJECT', too_long_name)
         self.assertEqual(too_long_name_truncated, slot_long.name_display, "this name should be truncated")
         self.assertEqual('OB' + too_long_name_truncated, slot_long.identifier, "this identifier should be truncated")
 
         # Test with different trailing character.
-        other_long_name = "This name is so long! It might look long, and that it is indeed!"
-        truncated_and_unique = other_long_name[:59] + ".001"
+        other_long_name = too_long_name[:-1] + "!"
+        truncated_and_unique = other_long_name[:251] + ".001"
         slot_long2 = self.action.slots.new('OBJECT', too_long_name)
         self.assertEqual(truncated_and_unique, slot_long2.name_display,
                          "this name should be truncated and made unique")