As the other person that replied indicated, *key is shorthand for Misskey and Misskey fork instances like Sharkey/Iceshrimp/etc.

There's a bunch of them and since many of the instances with primarily English or other language (besides Japanese) people on them aren't using Misskey (or any specific fork) it's easier to write *key.

I should have clarified that in the OP, but I hoped the body text would help with that. My bad!

@fediverse@lemmy.world