Dataminer Maksim "Gabe Follower" Poletayev spotted cs2.exe in the CS:GO files. This probably confirms the upcoming rebranding to Counter-Strike 2, something Gabe Follower previously denied.
The developers added cs2.exe into the official config files of CS:GO. It seems that it's indeed a rebranding?
Earlier that day, Gabe Follower reported on a leaked executable file of the CS Source 2 build that someone sent him. He contacted the developers at Valve, and, according to him, they confirmed it wasn't fake. He said they are looking for the leaker now.
There's also a series of patches marked as DPRP. According to Gabe Follower, Valve previously used the abbreviation DPR, which meant Developer Pre-Release.
According to Richard Lewis's report, CS2 will come out by the end of March in beta. It's unclear how exactly the transition will happen. Judging from a similar process in Dota 2, the Source 2 game might be tested alongside the original game to later replace it.