@sun Someone actually built that already. But I can't remember the name. Maybe @Sprate remembers.

It just used kind 1 events, actually, with an "r" tag of the URL.

There is actually another extension that predates it, though. @3bf0c63fcb93463407af97a5e5ee64fa883d107ef9e558472c4eb9aaaefa459d did it: https://github.com/fiatjaf/wen And he invented a new kind 34 event for this one.