>They're going to launch a browser update that removes support for most extensions
It's not like they're "removing" it, they rewrote half the browser and not all of the APIs are hooked back up yet. They're going to be added back eventually.
It was a preview release, but they've already started rolling it out to the regular Nightly channel and according to this very blog post we're discussing it's supposed to have a "public release later this spring".
Given that any changes have to work their way through the Beta channel, too, there's not much time left for landing changes in Nightly that will still make it into the first Release version... so the first official Release version that will be pushed out to everybody will indeed be in an unfinished state.
It's not like they're "removing" it, they rewrote half the browser and not all of the APIs are hooked back up yet. They're going to be added back eventually.