@jimp:
Yes, that is the correct function. If you keep the original file and then make a diff/patch from that to apply your changes, you can use the system patches package to maintain your alterations rather than redoing them after every update.
Generally speaking people using ACME/LE certs with pfSense will be using the pfSense ACME package to generate them, and we don't have an option for OSCP stapling in there, yet, either. So in terms of use with pfSense, probably not as common.
Understandable. I know this is a low priority, so I wrote teh code myself.
I've submitted a feature request https://redmine.pfsense.org/issues/8418
I've submitted a pull request https://github.com/pfsense/pfsense/pull/3927