This is the first time I am noticing this symbol on this post: https://discuss.tchncs.de/post/63754269/26869571

On lemmy.world (original instance) it looks like this:

I know the [M] symbol means the user is a moderator of the community, but what does the red shield to the left of it mean? I don't seem to have that on the communities I am a moderator of, and wasn't able to find anything in the documentation.