Explanation

In the new 1.19.1 pre-releases Mojang seems to have accidentally added a system to report players. This bug allows players to report other players on multiplayer servers. After looking through language files, it seems Mojang also seems to have accidentally implemented a ban system where players are banned from both multiplayer and realms.  

How to reproduce

To open the player report menu, one must simply enter the social interactions menu on a multiplayer server and press the "yellow warning" icon next to a player's name to access this secret menu.  

I hope Mojang is able to find this bug and remove it as soon as possible before it makes its way to release.