In this supplemental section, we'll crack open an EPUB file and have a look at its innards.
Coming Soon: a more detailed walkthrough on how to crack open an EPUB and sift through its guts.
Please note: it requires third-party software to crack open a MOBI file. This is considered infringement, and is therefore in violation of Amazon's Terms Of Service, so I will not be showing anyone how to do this. I haven't done it and don't ever plan to, so I don't know how anyway.
For now, if you're feeling ambitious to enter uncharted waters:
Create a copy of an EPUB file already in your possession, or download crackmeopen.epub below.
Using Windows Exploder, change the EPUB's file extension to .zip instead of .epub.
Extract that sucker and go poke around in there to see for yourself all the pieces and parts that make up an EPUB file.