There are two functionalities for renamign attached files.

In the entry editor

in "Quality" > "Cleanup entries"

The text of both menu entries should be the same. It needs to be changed to

Rename files to configured filename format pattern

Change "Filename format pattern:" to "Filename format pattern (from preferences)"

Also change "Rename only PDFs having a relative path" to "Rename files having a relative path only"

See #12565 for a step-by-step instruction for triggering rename of a single file in the entry editor.

Hint: https://devdocs.jabref.org/code-howtos/localization.html

Related: #11368