Just about everything that has to do with Microsoft's new Chromium-based Edge browser has leaked before it has launched. For example, a build for ARM64 PCs leaked a while back, and that's still not publicly available. It also leaked for macOS ahead of its release.
Now, as spotted by Microsoft leakster WalkingCat, a build from the stable channel has leaked. Unfortunately, it doesn't seem to actually work just yet. Also, it's worth noting that even if it does install, it's not going to give you anything different from what you can already get from the Dev and Canary channels.
A new Edge Beta build leaked as well, although this is somewhat less exciting. Edge Beta also leaked in May, and if you installed it, you're still getting updates.
As you probably know, Microsoft's Chromium-based Edge is only available in the Canary channel - which is updated daily - and the Dev channel - which is updated weekly. The Beta channel has been listed as coming soon since public testing began, and that will be updated every six weeks. There's still no ETA on an actual stable release.
So it's worth noting that the stable release that leaked isn't an actual stable build. It's the same thing that we're seeing in the Dev and Canary branches, but pushed through a different channel.