"Used to be" seems to be the operative sentence, unfortunately.

I have browsed various sources around the "Systers organization" keyword and what public repositories there might be, but no luck finding anything that includes the dynamic sublists implementation.

I have found the document that describes the implementation, on (the old wiki?) wiki.list.org https://archive.vn/NLyl2

Based on that document I assumed the following rpm to contain the changes, but no luck. https://ftp.osuosl.org/pub/osl/systers-mailman/ (unpacked with "rpm2cpio ../mailman-systers-2.1.12-2012.12.27.el6.src.rpm| cpio -idmv")

I think the document in itself can be a starting point for the implementation.

If you have a contact email to someone that's part of the Systers group, it might be worth reaching out in order to upstream this feature.

But I also have no issue with just diving into the codebase and building the functionality along the lines of the aforementioned document.

On Sun, Feb 14, 2021 at 6:00 AM Stephen J. Turnbull < turnbull@sk.tsukuba.ac.jp> wrote:

Marius Ghita writes:

...

To that end, I would propose a new feature for Mailman to allow the user to be more selective with the emails it receives.

This sounds a lot like the "dynamic sublist" feature that has been implemented in the Systers' fork of Mailman. (They use Mailman as a front-end for a lot of Systers-specific process, so upstreaming the dynamic sublist part is not trivial.)

Their repository used to be at git@github.com:systers/mailman3.git if you want to take a look. (Note: I haven't been involved there for several years. Their Mailman apparently was mature enough for them, and their GSoC goals moved toward mobile app development, so they didn't push to get GSoC students and we drifted apart).