Related question: Idiom for a person who knows every detail about something (which is also coincidentally asked by me!)
I'm asking for an idiom describing the details themselves, not the person who knows them. Some of the answers in the above link would be valid here, like jot and tittle.
My own guess would be something like this:
Since he developed this software framework himself, he knows the _____ (and) _____ of it.