Okay, my PHP 7.4.33 now has a pre-patch (read: incomplete patch) for a known newer CVE. I never applied that to either supported 8.x version I have because it will make it to the next normal release cycle.

PHP 5.6.40 does not have the code snippet I used from the Github repo; it does not exist in its current form.

I also compiled ICU4C 79.1 for this server, but I will only apply that to the next 8.6.0 release, which is RC5.