Sounds like this is something developers bake into their apps, not something the phone enforces.
ie, if I develop an app, I can have the app check a special google “Integrity” API and if I get no response (or a negative response), just have the app close.
This is exactly what it is. It is not enabled by default, a developer has to specifically enable it. Meaning the developer wants to force you through the Play Store for whatever reason they may have.
Sounds like this is something developers bake into their apps, not something the phone enforces.
ie, if I develop an app, I can have the app check a special google “Integrity” API and if I get no response (or a negative response), just have the app close.
This is exactly what it is. It is not enabled by default, a developer has to specifically enable it. Meaning the developer wants to force you through the Play Store for whatever reason they may have.