The extension is installed as of Special:Version. By browsing the extension's git history, seems it was removed from desktop beta features by dbb73c389d73aef805d7b52f980922106d9d8bcf (see T146436 and T160076 too; commit authored by @Jdlrobson). Hence removing Wikimedia-Site-requests (extension is enabled, nothing for us here) and Regression (the behaviour seems to be intended from some reasons).
From our end it's just a config change but the process will need to be followed:
Specifically a link to discussion about enabling the feature. :)
The conversation is old but it looks like the vote was in favor of doing this. 5 votes to 1.
That said it's been a couple of years so I'm declining this task. Please feel free to reopen it if you do want it enabled.