Extend systemd-boot/systemd-boot-builder

Is there a reason why BOOT_ENTRY title is hardcoded and not made extensible? I would like to alter the title displayed during systemd-boot to a custom title (e.g. last git commit message) but nixos doesn’t seem to have a way to do it. What was the design decision to make it non extensible? will i screw up majorely if i alter the title it to display my desired format?