For a very recent example of how new changes can get proposed and semi-implemented, check out https://discourse.elm-lang.org/t/a-faster-list-map-for-elm/. This thread is a great example, IMO, of how various memebers of the community have come together to suggest an improvement for Elm, have a plan for testing it, and Evan even responded to it. This is also a very “minor” change compared so one can see that there’s still a lot of process involved.
Alternatively, I wrote on /r/elm a few days ago about placing more focus on the Elm ecosystem and not just the compiler/core language. There’s a ton of active and frequently discussed work going on around tooling that is both highly important to any language ecosystem and is often ignored. You can check out GitHub - jfmengels/awesome-elm-sponsorship: Elm profiles to sponsor for a lost of people who are putting a lot of work into tooling and could probably use a lot more help than Evan. I don’t know this for certain as I’m not a contributor to these or to the core team. Just the sense I get from listening.