Considering the Microsoft Edge Stable channel link from Microsoft website now appears to the public on Google search and Chrome 78 to release today on October 22, 2019, there could be a chance for Microsoft to launch Edge Stable based on Chromium 78 very soon.

FYI, the stable version of Microsoft Edge is already leaked and available for download, the setup file is indeed from Microsoft servers and signed by Microsoft.
If you now search for “Microsoft Edge stable” on Google, the first result you’ll notice is from Microsoft which when clicked, downloads the Edge setup file and installs a stable version on your computer if you run. Do know, this will replace Classic/legacy Microsoft Edge and you won’t be able to uninstall Chromium-based Edge thereafter.
As of now, Edge Stable and beta are on the same version 78.0.276.19 and stable is based on Chromium v78.0.3904.63. Today, Google and Mozilla to release Chrome 78 and Firefox 70 versions, will there be Chromium-based Edge release as well from Microsoft? Time will tell.

Do note, Microsoft Edge stable channel isn’t yet officially launched and also is not available on the Microsoft Edge insider homepage. We’ll let you know when that happens.