If you want any of this, why don't you found a Verein and have open source activities as the purpose?
All in all I an very much against this. Mostly because I think Ehrenämter, as they exist now, are pretty stupid and pointless and because I strongly believe the state should not get involved with this at all.
Such as? By definition, open source projects are provided to the public, for free. That’s obviously a good for the public.
Note that in order for something to be a public service, it need not be useful for every member of the public. Most people have no interest in curling, but that doesn’t mean running a non-profit curling club that is open to everyone isn’t a public good.