DeletedUser443 Releases are not exactly experimental, rather everyone (in the Stable (default) update channel, Beta update channel, and Alpha update channel) receives the exact same OTA update package regardless of channel, but the OTA update is moved gradually, first it reaches the Alpha channel, then Beta, and then Stable, unless the GrapheneOS team decides to pause this process due to discovered issues. With major new versions of Android, they've sometimes released versions they know have some known issues or they've forcibly enabled the reporting of system crashes (this is normally a user-controlled toggle, I believe the toggle stays when they forcibly enable it but its state is simply ignored) because they want to collect feedback — so they know in advance that they won't move the release/version into the Stable channel without making a new version in the near future to fix the known issues and stop forcibly enabling reporting of system crashes.
2025063000 was their first public release based on Android 16. It wasn't moved to Stable. (They also added the "with all GrapheneOS features available" bit because shortly before Android 16 was released they've said they're gonna need to drop GrapheneOS-specific improvements in order to quickly move to being based on Android 16 to have the latest security patches, but it turned out to not be needed because they could backport the patches to the Android 15 QPR2 releases.) The 2025070800 release was the first one to be moved to the Stable channel, for all devices, including the Pixel 9 series. (The Pixel 9a device specifically received the 2025070800 release somewhat earlier, the GrapheneOS team said here on the forum that Pixel 9a had a "Frankenstein" GrapheneOS until Android 16 (excluding Android 16) so it had a lower quality barrier and they felt comfortable pushing it to them earlier than for the other devices.)
DeletedUser443 Out of pure curiosity, would there be any benefit to ever go a slightly older version hardware like a pixel 8 pro rather than a newer version since the software has been out longer?
The Pixel 9 series is already old enough, the Pixel 10 series should be released in a week or a few from now.