Most of the most changed parts of those two libraries are sprinkled around the forum so if you’re interested in seeing how they are used you’re going to have to use the search function to dig them up.
Usually, people just want to adjust the charging current, input voltage limit, and charging voltage.
I think it’s more that it’s baked into the firmware and they really would rather these settings not be messed with unless you know what your doing since the wrong settings could cause damage or overheating or less than desirable performance.