In my custom extensions’ TCA I am updating FAL reference fields to work with TYPO3 v12/v13. Previously I had defined a fieldname which was a camelCase version of the TCA/SQL fieldname (imgRel for img_rel: first argument of getFileFieldTCAConfig()) This camelCase value is now stored under sys_file_reference.fieldname – but TYPO3v12 searches for img_rel and therefore does not show referenced files.