While rebuilding the Quibble images:
2024-03-19 11:04:11,572 [docker-pkg-build] INFO - W: GPG error: https://packages.sury.org/php buster InRelease: The following signatures were invalid: EXPKEYSIG B188E2B695BD4743 DEB.SURY.ORG Automatic Signing Key <deb@sury.org>
The ./dockerfiles/sury-php/sury-php.gpg got last touched on March 18th 2021 by 49281f5fd7a1410a19d722bc6b0f58ca9ce69c43 , thus I guess it has indeed expired.