So, we have two kinds of example tags, from what I can see. The first is when you ask a new question, before tags are entered, three are provided as suggestions. For example, today it says (for me) "at least one tag such as (fate monk feats), max 5 tags". Previously, I've seen (fate monk feats) replaced with stuff like (rules-as-written pathfinder gm-techniques) as a random example I might not actually have ever seen, so I know those tags change, probably frequently.
Then, on the side of the new question page we have, when the tag line is selected, the "How to tag" guidance. This guidance states, in part: "combine multiple words into single-words with hyphens (e.g. dnd-5e), up to a maximum of 35 characters". I don't know that it ever doesn't say dnd-5e, but it might.