Yes, there is. GH_IO.dll basically allows you do to this (and many other things). Some of the internal structure of these things are not documented properly, but it’s not hard to understand it, so, I did that in order to create/update our own ghuser components.
I’ve seen Ladybug has a super interesting approach in which the python code and metadata of components is stored in plain-text files, but I was not able to find the code they use to generate .ghuser files out of them, so I built a tool to do just that: take python code + json metadata + png icon and turn it into a .ghuser file:
(I am pretty sure @Mostapha has something similar for Ladybug, I just couldn’t find it anywhere)
I hope this is useful to others as well.