Where are they? For instance I can't find changelog for Pixel 3 - SP1A.210812.016.C2.2022112800.

a month later

I have the same question. My Pixel 3 has installed many updates over the past months and each time there's been zero trace of said updates online aside from a new image name on the changelog page. No patch notes, no info on the forums, no info on Reddit, and even clicking on the image's hyperlink gives me GitHub's 404 page. I still have no idea what my phone's actually been installing in the background.

Where can we find a changelog for this? I can't even find an option in Settings to disable automatic updates so I can't prevent these unknown updates from being installed.

As far as I know, there are no changelogs for these devices because they're even beyond extended support at this point. Updates include things like Vanadium updates as well as changes to get Sandboxed Google Play working again.

    matchboxbananasynergy Understood. Definitely grateful to even be receiving updates, assuming they're official. Continuing to use my Pixel 3 with the expectation of not receiving any updates until my situation changes. However, it would be handy to know what these system updates are actually changing.

      dee A rough outline of what changes is mentioned in the alpha/beta testing room on Matrix when the releases first come out. But yes, the releases are definitely official, though sparse :)