According to the latest leaks, Red Dead Redemption 2 battle royale will have up to 32 players and will be called Make It Count. The mode is not implemented yet, as the Red Dead Online implementation progresses fairly slow for Rockstar.
Make It Count will have four maps at the start, with two different starting weapons. The portion of Make It Count unfolding on Saint-Denis Plantation and Tall Trees maps will have players fight each other in a shrinking circle, starting "with a bow and a handful of arrows" which sounds like the basic start of any battle royale game.
Players will likely need to go around the place, looting anything they can in order to get their hands on better gear and outlast their opponents. Stillwater Creek and Strawberry maps might have a trickier start as players will get "a handful of throwing knives" instead of a bow and arrows.
Either way, the leaked files clearly state that the playable area will be shrinking and the is to be the last man standing. It remains to be seen when this mode will become playable though, since Rockstar have put a disclaimer that Red Dead Online is still in beta as it is not finished.
This may soothe the players who will have to wait a few more days to get their hands on the online component, in case they didn't purchase the Ultimate Edition for early access. Those who played on launch day and weekend also get the online component sooner, so you may want to check the Red Dead Online launch schedule.
Granted, some fans may be put off by the fact that the battle royale mode will not have as many players as it does on other heavy hitter games such as Fortnite or PUBG, but no one saw it in action yet.
It could be that the maps were better suited for a lower player count, or simply that Rockstar never planned on making a session available for more than 32 players. Whatever turns out to be the case, the smaller format could provide quicker sessions, with more action than the competitors, along with shorter queue times on smaller servers, due to not need to wait for a ton of players to join the game.