Today is a big day for Microsoft's Edge browser, which is now officially available as a Chromium-based browser instead of the old UWP version that ships with Windows 10. However, the initial release has some significant limitations, like the absence of history and extension syncing, and the lack of support for ARM64 devices.
Microsoft has been testing ARM64 versions of the new Edge browser for some time in Insider channels, but it was too late to make it to the official release. Now, about a month after it debuted in the Dev channel, ARM support is now live in the Beta channel of the Insider program, too. The ARM64 builds will replace the x86 versions of the browser on devices where they're supported, but Microsoft is pointing out a known issue with the ARM builds, which is that video playback may not work properly on some websites.