Jiacai Liu over at Keep Coding has an interesting post on the Emacs package system. The post is nominally about maintaining your Emacs configuration but is actually a quick overview on how the package system works.
The problems that he’s trying to solve is that of version control. Sometimes an update for a package will appear in Gnu ELPA or MELPA but will turn out to be broken. It’s pretty hard to recover from that so Jiacai uses the Git submodule system to help solve the problem.
In order to do that, he needs to manage the package configurations manually and that means understanding how the package system does it. Jiacai explains the autoload system and how the require command works.
If you’re a bit fuzzy on how package loading works, take a look at Jiacai’s post.