I think this is a hard problem to solve because actual invitations seem to not work well. In other words, writing to someone and asking them in specific seems t

I think this is a hard problem to solve because actual invitations seem to not work well. In other words, writing to someone and asking them in specific seems to not go good places. I think it works better to focus on a) making sure to create a welcoming or inviting atmosphere and b) leaving the door open logistically. It needs to be apparent to other people that new contributors are welcome and it also needs to be apparent to other people where and how they can go ahead and step up to bat. These can be tricky things to pull off. It is much, much easier conceptually to just think "I know! I will actually literally invite people!" (aka ask them to contribute) and this means you may be asking people who have no interest in the project or not ability to effectively contribute or both. I am still working on solving this piece for my own projects. Trying to be inviting without literally sending out invitations is tricky. But I think that is what works best to make it possible for those who have both interest and ability to get involved on terms that work for them.