Mouse and NDOF events are defined in enums that are never used directly by RNA through RNA_def_property_enum_items. As a result, they don't get automatically extracted to the translation files and need to be manually, through N_() macros. The translation context used is the same as in other places related to KeyMapItem: "UI_Events_KeyMaps". Pull Request: https://projects.blender.org/blender/blender/pulls/116390