Thanks for reviving this topic and asking. to quote my comment a few min ago in √ Craft and Hook compatibility - #14 by LucB :
Drafts recently added an x-callback-url Hook can use in its Get Address tab. However, Hook has not yet been updated for this. It was / is , coincidentally, the next item on our integration update list. We hope to publish an update tomorrow on the forum.
I.e., Hook will use that x-callback-url.
If you’re asking whether Hook itself uses x-callback-url, not currently. We’ve published an AppleScript dictionary instead.