Microsoft announced a bunch of new features for its Chromium-powered Edge browser this week at Build. After demoing Edge for macOS, it wasn't long before that leaked. Now, an Edge Beta build has leaked.
Previously, Edge has only been available in the Canary and Dev branches, with Beta labeled as coming soon. Canary is updated daily, Dev is updated weekly, and Beta will be updated every six weeks, and it's meant to be the most stable.
That's why there's no real reason to install this build. While the download does come from Microsoft servers and it seems legit, those looking for the most stable version probably aren't going for a leaked build. There's no guarantee that this will actually be the beta build that's released to the public either. The only certainty here is that it has the 'Beta' icon.
The leaked build comes in x86 and x64 flavors, so there's still no option for native ARM64. That does seem like a strange thing to leave out for a beta, which should be somewhat feature complete and the last step before being public. Windows 7 and 8.1 support should be coming as well, although it's not clear if that's included in the beta.