In stock Android systems, "Google Play System Updates" aka Project Mainline / Modular System Components (https://source.android.com/docs/core/ota/modular-system) deliver APEX component updates to the system independent of system updates, not Play Services or Play Store. Despite the monthly cadence of Pixel system updates, the stock OS still gets Play System Updates of various sizes from time to time, and it has a YYYY-MM-DD update level independent from the patch level as well.

I was wondering what is the relationship of GrapheneOS system updates and the modular components delivered by Play System Updates, since there is no such mechanism in GOS?

Are (all of) these modules part of the GOS build and updated together with the rest of GOS?

Any reason why they aren't updated together with the Pixel's stock OS and thus necessitating separate updates by clicking that option in settings? Is there a way to view individual versioning of the components being updated so we can be sure that they're updated in GOS as well?

Thank you.

GrapheneOS currently doesn't ship mainline APEX updates due to the difficulties in building and shipping them.

Security patches from mainline APEX updates are included in monthly and quarterly AOSP releases that GrapheneOS is based on.

    Thanks for the information @Carlos-Anso and @muhomorr.

    muhomorr Security patches from mainline APEX updates are included in monthly and quarterly AOSP releases that GrapheneOS is based on.

    Just to confirm, this means that feature updates are not included in the monthly/quarterly updates in AOSP and only in the major releases? The thread @Carlos-Anso linked to mentions that Google has "recently" (Jan 2023) tagged APEX updates after they're rolled out. Are these not included when GOS updates from AOSP?

        doodle
        These updates are good for the endless stock phones which not longer get OS updates, or get them late. Unfortunately not so good for GrapheneOS.

        The feature updates are not included in monthly AOSP. Security patches are. Complexity involved in building these currently means that GrapheneOS only gets feature updates with major updates. IIRC they are also in the point releases (eg. 12.1) but they dont happen every year