FWIW, coming back to making a proxy plugin again years later, I'm still confused by this plugin data stuff. It also doesn't help that `pdata` is not a good name and [the `@param` doc-comments are missing](https://github.com/geany/geany/blob/770cda40646e8ebfe6591df03356e2bcb71b875c...).

Once I figure it all out again, I'll look at improving the parameter names and doc-comments.