Breaking: #105855 - Remove file backwards compatibility for alt and link field 

Description 

Back then, when FAL was introduced, the Core file fields media for table pages as well as image and assets for table tt_content had their so-called "overlay palettes" overridden to imageOverlayPalette, so that additional fields like alternative, link and crop were displayed. However, this was done for all file types, including text, application and the fallback type unknown. For these types those additional fields serve no meaningful purpose. For this reason they are now removed.

Impact 

The Core file fields media for table pages as well as image and assets for table tt_content will no longer display the fields alternative and link for file types other than image.

Affected installations 

This affects installations, which use one of the named Core fields for file types other than image (for example text or application) and make use of the fields alternative and/or link.

This should not affect that many installations, as these fields are used most often for images.

Migration 

In case you need those fields back, they can be brought back with TCA overrides. First, register a new palette for the sys_file_reference table with the needed set of fields.

$GLOBALS['TCA']['sys_file_reference']['palettes']['myCustomPalette'] = [
    'label' => 'My custom palette',
    'showitem' => 'alternative,description,--linebreak--,link,title',
];

Then, use this palette for your specific Core field and file type. This will bring back the fields alternative and link for the media field of table pages, when the file type is text.

$GLOBALS['TCA']['pages']['columns']['media']['config']['overrideChildTca']
    ['types'][\TYPO3\CMS\Core\Resource\FileType::TEXT->value]['showitem'] =
     '--palette--;;myCustomPalette,--palette--;;filePalette';