@apps @jenniferplusplus Conversations has been able to open xmpp: URIs (without //) for years.
Just to be sure I tested this with web+activitypub: URIs quickly to make sure web+ URIs don’t get special treatment - and it’s working fine in both Firefox and Chrome on Android.
Here is the intent filter I was using: https://gist.github.com/iNPUTmice/79757b4edc5fbfc8c9aab2b965cdcb87
I have no strong opinions on whether the // should go in there. But I’m advocating for consistency. (And clarity in the FEP)