I've recently noticed (mainly as I'm a recently new member) that a lot of song-Id questions are stated as being off-topic in the comments. However I haven't seen links to (semi or otherwise)- official policies on the topic. There are many conversations about it in meta here, but I don't know if any of them are the consensus on the issue that we can refer people to. (and by consensus, I mean general agreement in the community or decisions made by the moderator team)
So, to be clear, I'm not asking what makes a song-ID question on- or off- topic, but if the rules on that have already been decided and, if so, where we can point people to when those types of questions are asked.