I could not find a specific "solid feature" or official documentation for a file named .

: Compare part10 to part09 . Multi-part RARs (except the very last one) should typically be the exact same size.

If you are looking for a "feature" because the file is giving you trouble, try these steps:

: Ensure you downloaded it from a verified source to avoid malware disguised as a software repack.

: Many uploaders provide .sha1 or .md5 files to verify that your specific part10 isn't corrupted.