@SapientPearwood @hellhammer666 @Owl @nordtrack @Owl @GabeLakmann @BroDrillard @anonymous @PurpCat I took the room ID from this message and can't actually locate the message within that room.
But I found some other messages that ALSO seemed to have that room ID, implying that room got searched twice from one pull of /joined_rooms, which should not contain duplicates:

yun-wuxin:[wisknort]:~/tinker/matrix$ curl -sH "Authorization: Bearer $TOKE" $INSTANCE/_matrix/client/r0/joined_rooms | jq -r '.joined_rooms[]' | wc -l
444
yun-wuxin:[wisknort]:~/tinker/matrix$ curl -sH "Authorization: Bearer $TOKE" $INSTANCE/_matrix/client/r0/joined_rooms | jq -r '.joined_rooms[]' | sort | uniq | wc -l
444

So I think actually it means that somehow it was displaying the wrong room ID. So I still don't actually know what room it was in, and thus can't pull context, like an actual link to kyun.
...
Or I could just search all rooms again, for "kyun".