Linn is not listed but it is my understanding that streaming to Linn is using a Linn specific protocol (or really, their implementation of an open protocol) and not RAAT. For this reason, I expected Linn to be called out here. Oversight on the FAQ?
You are correct, there should be an entry in the FAQ for Linn. If you have Linn streamers (as I do), they show up in Roon as Roon Tested, streaming via Linn Streaming (which I guess in Roon’s name for Linn’s implementation of Songcast.