The link to Phabricator in /includes/Forms/MetadataDetectForm.php from rEGWT7328cc3345772c81a8f4c9611f93305581100b65 does not set a parent task ID and does not set Commons as a project tag, for example, while the link on Commons does. The source code currently says:
The link on https://commons.wikimedia.org/w/index.php?title=Commons:Upload_tools/wgCopyUploadsDomains&oldid=427848497 uses this link instead:
Both should be in sync.
Pointed out in T261575 by Christian (thanks!).