I noticed that first-posts is a synonym of new-users. While the term "first posts" can refer to the first posts made by new users, the words "First Posts" can also specifically refer to the review queue First Posts.
I think there should be a tag for the First Posts review queue, given that its mechanics are different from most other review queues (e.g. able to access with only 500 rep, a single review dismisses the task, can take any action or no action, etc.) and because we have a tag for the late-answers queue, which has similar mechanics.
Should we de-synonymize these tags and redefine the first-posts tag to clearly refer to the review queue (and not just general "first posts")?