@aljoscha they are part of the javascript process. They allow people to extend the sbot database without having to debate wether a given thing should be a core feature, most plugins would not have been merged as pull requests because it would make sbot totally unweildly!
I hope one day we have some clever sandboxing thing that handles all the plugins and that we can indeed write plugins in other languages than javascript, but I don't know how that will work yet. (I think wasm will be important here though)