2. a delta

The delta is 'ar' archive (see 'man ar'). The delta contains 'info', some data members (named by numbers), a script named 'patch.sh.xxx', and optional gpg signatures. The script recreates the new deb. See do_delta_() in the python code for more details.

2.1. the info in a delta

a delta first 'ar' member is always named 'info', and is a text file containing some keywords and informations regarding the delta itself. [TODO add details]

2.2. how to apply a delta

TODO WRITEME. You may look into /usr/share/debdelta/debpatch.sh to understand the basics.