[tduberne]

This was my question as well. I was myself directly involved for about 10 years in the development and maintenance of a medium-sized open source project, and am still part of the community, and there was never really any form of "external contribution", appart from the occasional user who found a problem in the docs or a small bug and was knowledgeable and kind enough to fix it and submit a PR (less than a handful in 10 years). And we typically would already know the guys from conferences or similar.

I feel that the user is coming from a place of wanting to gather experience and show it, and read somewhere that open source is great for this. But lots of projects are open source not to favor external contributions, but for other reasons. And external contributors will typically be long term users of the software, who already have deep knowledge about it and a personal interest in moving it forward.

If the aim is to get experience, I am actually convinced that it is easier to get an entry-level job than to invest the time and effort to be able to make significant contributions to big open source projects. Of course if you manage to get a job where you can contribute to open source, even better.

Good luck!