Based my first hand account - there are very timid attempts to open source some libraries - mostly used in between the EU institutions. Code given as a zip, no access to a repo.

There is plenty of anxieties around the subject still, so work does not take place in the open.

Supporting Open Source projects that are used internally are still deep in the woods, ironically thought one could find reference in documentation to “helping out the community” as a stated benefit of using Open Source...