Wine compatibility layer leader Alexandre Julliard announced the sixth release candidate for Wine 6.0 and it looks like this will be the last before a final release.
It's not set in stone that the next will be the big 6.0 release but it will be if they don't see any big last minute issues. If they do manage to keep to the schedule it will make Wine 6.0 join Wine 2 / 3 / 4 / 5 with a January release, whereas Wine 1.0 had a June release.
Keeping in mind Wine is currently in a feature-freeze, meaning no new features are going in it's only bug fixes until the flood gates open for the 7.x development series. For the RC6 release only 10 bugs were noted as fixed including issues like Commandos 2: Men of Courage hanging after launch and World of Tanks not working with some locales and a SteelSeries Engine application crash.
See the release announcement here.
What is Wine? It's a compatibility layer for running various Windows-only applications and games on Linux and other operating systems. Tons of people work on it, with some sponsored or employed directly by CodeWeavers who have their special version with the CrossOver application. Wine is also the backbone of Steam Play Proton.