I am a member of the Robigalia project. If you'd like to discuss anything with us you're welcome to join us in our matrix room at https://matrix.to/#/#robigalia:matrix.org or the linked IRC room at OFTC #robigalia.
I'm glad you found our project useful!
We have abandoned our old code because we felt maintaining a separate version of the libsel4 python build scripts to generate rust was impractical for our project. We found it to be very difficult to keep in sync with seL4 changes.
While upstreaming this work is one solution, it just pushes the maintenance burden upstream.
We think a better solution is to improve the seL4 build system itself to make it easier to add language bindings, not just for rust but for any language.
To that end, we believe expanding the scope of the IDL so that libsel4 can be completely procedurally generated from it is the right thing to do. After that is done, I think it would make more sense to work on upstreaming something like this.
We have been experimenting with our own complete seL4 IDL and exploring generating a rust seL4 library from it and intend to share our findings. So far I believe a seL4 IDL will significantly reduce the amount of code, complexity, and maintenance burden of the libsel4 build system, since it removes the need to hard code the information about types, sizes, names, etc that currently exists in the python scripts.