Does anybody here know about what exactly Google's Carrier Services app (com.google.android.ims) does and why is it installable via the Play store (https://play.google.com/store/apps/details?id=com.google.android.ims)?
What I know is that it is used for RCS, but I have seen first hand that you can enable RCS in Google Messages app without Carrier Services being installed. My understanding is that Google Messages delegates to Carrier Services by default but it has its own RCS implementation that it uses as fallback in case Carrier Services is not available.
However, given the "ims" in the package name I was wondering if this app might do more? Could it be involved in provisioning IMS for some carriers? Could it theoretically enable VoLTE/VoWiFi in some scenarios where pure GrapheneOS won't be able to? Does anybody know?
If the above is true, would any extra (non-RCS) functionality even work if the app is installed as a normal user app? Phones that ship with it have it as a system app, and I presume it may require some system-level permissions.
I'm asking this just for curiosity's sake. I always wondered why Google has the Carrier Services app discoverable and installable via the Play store as an user app (a system app can be updatable via the store without it being discoverable, like Play Services). It can't be just for RCS since Google Messages by itself works fine without it.