So,I run /e/OS, and have done so for years. I don't understand what this will validate.
At present, Play Integrity is a means of telling apps that the software that's *actually* running on a phone, is the software that Google *expects* is running on the phone. Now, *in and of itself*, I don't see that as being a problem, because if Google says "this is a modified OS" or "this is a modified bootloader", apps can ignore this fact if it's simply informational. I submit that there should be a requirement for apps to divulge whether they will refuse to run if they are informed of a modified software stack, but any attestation mechanism should be limited in that way.
But let's assume that it's the case - as far as I'm aware, that's how it currently stands. The answer to ""Who" is validating "What"" is pretty simple: "Google is validating that unmodified software is running on hardware". An open source attestation mechanism breaks basically all of this.
an "operating system service" that apps can call to check whether the device's OS meets required security standards
So, even if we limited this to official builds of /e/OS and iodeOS (which is a big "if", since both have community builds, and are derivatives of LineageOS, and each have downstream derivatives), now, the app is trusting /e/OS...that the build is unmodified, of software that requires an unlocked bootloader in nearly all instances of its installation? Both OSes have integrated adblockers and other privacy tools, and MicroG that spoofs other data required for apps to run as if there were Google Play Services installed...so, are they saying "we solemnly swear that all of the anti-tracking, adblocking, and signature spoofing meets security standards"? Seems like conflicting signals to me.
a decentralized validation service that verifies the OS certificate on a device without relying on a single central authority
If we're stretching "decentralized validation service" to include the public key infrastructure that handles standard Sectigo/Thawte certificates, I guess maybe...but if we're talking something closer to the blockchain...what bank is trusting an anonymous group like that?
and an open test suite used to evaluate and certify that a particular operating system works securely on a specific device model.
Can we define "securely" here, and how a "specific device model" would factor in? Is even /e/OS looking to close the door on rooting and other kinds of mods? Is this the end of the road to /e/OS's community builds? Is this the sort of scenario where the presence or absence of Magisk would alter the calculus? If so, then why would a user choose an /e/OS device - especially if it means the removal of the MicroG mods that make regular Android apps work - over a stock Google phone?
I just can't see how this config can simultaneously keep the modders happy - the people who run /e/OS on their devices and donate to it - along with the banks and other companies who would want reliable attestation.