https://foldingathome.org/ is not a completely open source project, but there are parts of user faced UI (FAHControl) that are open source among with other things. This parts are poorly maintained despite a vast user base. For example, the software doesn’t work on Ubuntu without manual modification (patching path to Python 2). There are dozens of PR proposing the fix, but developer(s) are not responding.
I asked about the situation in official (again, non open-source Discord) channel and it appeared that the project has only one developer on the payroll. Because it is a University project and University work is sponsored by government grants, there are no ways to allocate funds for the maintenance of existing codebase. Only development of new and perspective research is funded. The University even don’t have cash to pay professionals to organize and raise the maintenance funds from the public. And all this is despite of impressive list of project ambassadors.