We are participating in Google Summer of Code 2022 (GSoC) under the Python Software Foundation (PSF). We did apply as a separate organization, but didn't get in. Many thanks to the PSF's GSoC organization for picking us up at the last minute!
You can find our ideas page at https://wiki.list.org/DEV/Google%20Summer%20of%20Code%202022, and item on the PSF ideas page under https://python-gsoc.org/ideas.html (which isn't so interesting about Mailman, but you can check out who else is under the PSF banner there).
Discussion and development of project ideas will take place on email@example.com.
If you have a developed idea not already listed that you're willing to discuss and advocate, and you're willing to grab the template (last item on our ideas page on list.org) and fill it out, please post it to firstname.lastname@example.org. (This a deliberate hoop-jumping exercise to filter in "serious" ideas.) You can put more weight on it by expressing interest in mentoring the project, and even more by actually volunteering! ;-)
If you have a half-baked idea, and/or you want to get input from other Mailman users, of course you should feel free to discuss it on email@example.com. We *might* pick it up from there, even if it's just a drive-by post with little support from the list members. But no promises about that, most of our attention will go to mailman-developers. If you feel some idea should get more love, polish it a little and post that to mailman-developers (don't cross-post, please).
Again, we'd love to have more mentors, including backup mentors. We currently only have two mentors. Although we're both core developers, and I'm on an academic schedule and can devote plenty of time to the student during the summer, not so for Abhilash.
Volunteering at this stage is not a promise to do more than look at student proposals. You would only be asked to look at the proposals, and volunteer as mentor for that project if you have interest and some level of knowledge to contribute to it. Even if you're a site admin with little Python programming experience, vetting interns' brainstorms about list admin-visible features and holding their hands until the "pros from Dover" arrive is quite helpful in making the student feel at home in our community. Many students are shy about blogging and communicating about their projects to the community -- just talking to them about their project and suggesting that they blog what they told you is helpful. Coding skills and knowledge of some part of the Mailman 3 code base are most welcome, of course, but you can make your mentor role what you want it to be.