For example a url like this used to work:
https://commons.wikimedia.org/wiki/Special:FilePath?width=100&file=At_char.svg
A gadget and a toolserver tool of mine now show broken images for all of these.
GET https://commons.wikimedia.org/wiki/Special:FilePath?width=100&file=At_char.svg
HTTP 302
Location: https://commons.wikimedia.org/w/index.php?title=Special:Redirect/file/&width=100
GET https://commons.wikimedia.org/w/index.php?title=Special:Redirect/file/&width=100
HTTP 404
Version: 1.21.x
Severity: blocker