Plugin structure

Hi,
There is code structure for this plugin or how the plugin its work step by step, I currently study the HLS plugin as homework and I need help to understand every single step, or if you can give me a hint from where I can do my researches.
Thanks

Begin by mapping the HLS plugin's existing structure and tracing its step-by-step workflow. The issue names no files, tests, or entry points, so first identify those before writing documentation. Done means providing a clear explanation of the plugin structure and how the workflow operates.

Written by the indexing model from the issue text.