"filepath" was misleading since this path could also point into a .blend
file. Further, the convention was to use "filepath" for such files, and
"file_path" for when only an actual file path was expected. This is
highly confusing and non-obvious. Plus a (newer?) function broke with
the convention.
Just be explicit about the type of path, even if a bit verbose. It's
good to always have the reminder that this may be more than just a file
path when passing it around.