elyprism launcher [sic] is a fork of Prism Launcher that doesn't require an account to play.
This isn't inherently bad or illegal, as the limitations this sets are the exact same as what you'd get when playing without an internet connection. Microsoft has never taken action against launchers that use authentication servers other than their own. No one needs to do M$'s job here. You're not helping anyone here, and it is very easy to just trick regular Prism Launcher into letting you play without an account, ElyPrismLauncher just lets you see your Ely.by skin. Ely.by (and therefore ElyPrismLauncher) has legitimate use cases outside piracy, such as setting up a "camera" account for video recording, without the possibility of someone hacking it, or for future-proofing the game after Microsoft inevitably stops updating Java Edition. https://aur.archlinux.org/pkgbase/elyprismlauncher-bin/