It's called a bugfix. I'm surprised Data didn't just name this 15a; for all intents and purposes it's just the version of 15 that should have come out if we weren't begging for quicker releases
. So no, the builds aren't going to start coming out every five days ... although that'd rule. You'd need one huge-ass company or an open source game to get that kind of activity (e.g. nightly builds).