Apparently this is a 1.7.4 preview for BotW, currently on reddit, source is from dev on discord.
Would love if someone from the patreon could confirm. Looks pretty playable, major collision / physics issues appear resolved.
Edit: Appears legit, the release date for 1.7.4 is April 2nd
I'm positive those dudes are wizards. That release date is less than a month after BotW came out.