For an image - say: https://commons.wikimedia.org/wiki/File:Aris’s_Birmingham_Gazette_-_1771-11-11_-_p1.jpg - the default markup provided by the "Use this file" link on the toolbar is:
[[File:Aris’s Birmingham Gazette - 1771-11-11 - p1.jpg|thumb|Aris’s Birmingham Gazette - 1771-11-11 - p1]]
The right hand part of this ("|Aris’s Birmingham Gazette - 1771-11-11 - p1]]") repeats the filename. It should instead (where available) use the caption from the file's structured data, in the user's preferred language:
[[File:Aris’s Birmingham Gazette - 1771-11-11 - p1.jpg|thumb|front page masthead of Aris’s Birmingham Gazette, 11 November 1771 edition]]
This applies to all the applicable markup snippets under each of the "Use this file" links on a file page; for example the non-thumbnail wiki markup and the alt attribute under "Embed this file".