Between 2016 and 2018, the Minecraft community was split. Java players had launchers like MultiMC and the vanilla launcher allowing version switching. Bedrock/Windows 10 players had... nothing.
The launcher utilized a process known as "UWP (Universal Windows Platform) AppxManifest spoofing." It tricked Windows into thinking an older, unsigned version of the game was a legitimate Microsoft Store app. It would then: mcmrarm mc-w10-version-launcher