Default [Q] How to edit/modify feature.xml in a flashable zip?

I've created a MOD and a flashable zip file to install it.

The issue, for which I cant seem to find any help on is:

On certain devices it is required to edit the /system/csc/feature.xml file.

I dont want to replace the file all together, but just add some lines (if the set isnt there) or edit the lines (if it already is there).

I figure its just some code i need to add into the updater-script, but dont know where to start?

Any help would be appreciated.

TIA.