Not immediately clear to me, is this limited to ghu_xxx type OAUTH tokens? And it's only relevant for PHP projects that use composer in GHA?
That's my understanding. This seems to only effect PHP projects that use Composer in GitHub actions. Examples being usage of shivammathur/setup-php and or php-actions/composer.
It's limited to ghs_ (server to server token's), that have the new format enabled: https://github.blog/changelog/2026-04-24-notice-about-upcomi... (and actions that use the vulnerable package)
This include's the GITHUB_TOKEN that is builtin within a actions jobs.