Comment by weinzierl

An e.V. in Germany mostly makes sense if it is also charitable. You will have a hard time justifying that for an arbitrary FOSS project.

There are about 100 categories that are predeclared as potentially charitable and you have to fit into one of them. Most of them are weirdly specific like homing-pigeon breeding or model plane flying.

The only two that are broader and remotely realistic candidates for a FOSS project are religion and education.

If you don't want to start a cult you are left with education. That is as how organizations like Chaos Computer Club do it. Education means education for the general public though and it is not enough if you offer occasional courses for a niche topic. It has to be something that potentially interests everyone. The tax office is checking that and it is on you proof it to them regularly.