It seems, as discovered by Mark Kirby, that Mateo created the room (on June 26th 2012), with the purpose of coordinating voting.
Why would one want to coordinate voting? Well, questions with no answers and a negative score are automatically deleted if they haven't been active recently. It's evident from the conversation leading up to the creation of the room in Ask Ubuntu General Room (from which is seems that the idea of setting up the room was actually jokerdino's) and the second day of the room's transcript that causing unanswered, low quality questions to be deleted by downvoting them was one of the room's purposes. The chat in AUGR also gives the original name, which was Crusaders of the Lost Downboat.
Mateo was the only owner of the room at the time of creation, but promptly made jrg an owner so that he could add a feed. But jrg was a moderator at the time so he did not need to be a room owner to do that and Mateo removed him as an owner. jrg made jokerdino a room owner on July 10th 2012. jokerdino was not a moderator at the time; he was elected in 2013. Eliah Kagan was made a room owner on July 12th 2012 by Mateo, who also added ish to the list of owners on August 5th 2012.
The room was frozen for inactivity on October 2nd 2012 (just a few months after being created).
The room was unfrozen on October 5th 2016 by jokerdino, so that he, Anwar and I, and anyone else interested, could use it for a project for which we had previously been using the Ubuntu Regulators room, which had been used for moderation purposes (it was created on 10th October 2010). Some users wanted to use that room for another purpose than our project, so we vacated it. At that time, I expressed concern about the word 'crusaders' and jokerdino changed that word to 'raiders'. That's how the room got its current name. jokerdino added Anwar and myself (neither of us were moderators at the time) as room owners when it was unfrozen in 2016.
The room was used for the query project and, increasingly, for general moderation* purposes, as today. Here is a non-exhaustive list of the current uses of the room in no particular order:
- Discussing how to improve posts or their situation. What should we do with this post?
- Discussing all other matters of moderation policy (anything that would be on topic on meta).
- Asking or explaining how site features work and do not work (anything that would be on topic on meta).
- Pointing out good, underappreciated posts that deserve upvotes.
- Asking for duplicate targets for questions (because you know it must be a dupe but you can't find a good one).
- Identifying questions that can be answered based on the comments, and encouraging commenters to answer or posting community wiki answers based on those comments and upvoting them.
- Sharing posts that should not be closed so others can vote to leave them open.
- Sharing posts that should be closed so others can vote to close them.
- Sharing posts that should be reopened so others can vote to reopen them.
- Sharing posts that should be deleted so others can downvote or vote to delete them.
- Identifying and salvaging and/or undeleting wrongly deleted posts (by voting to undelete or flagging for moderator attention).
- Sharing posts that should be flagged so others can flag them (Smoke Detector is most active in this particular field).
- Interacting with Bhargav Rao's bot Natty, which finds possible not-an-answer posts.
- Moderating review queues (checking that they are being used properly).
On 25th June 2020, jokerdino added Kulfy, who had long been a highly active participant in the room, to the list of the room's owners.
The list of room owners is public. Nobody except jrg has ever been removed as an owner so the owners are Mateo, jokerdino, Eliah Kagan, izx (ish), Anwar, Zanna and Kulfy.
* "Moderation" is meant in the broad sense of community moderation, which includes voting, editing, flagging, commenting, closing, reopening, deleting, undeleting, determining policy etc, not specifically the activity of diamond mods. Raiders of the Lost Downboat has no access restrictions. All users are welcome to participate, to visit and ask for help on moderation issues there.