Review code documentation

The documentation in the code should be reviewed to ensure it is up to date with the code it describes.
This is particularly helpful for newcomers as sometimes understanding what and why is happening in some parts of the codebase can require additional information.

This can/should be split into multiple smaller issues to address specific parts of the codebase.

The issue names no files, tests, or entry points and explicitly suggests splitting the work into smaller issues. Start by selecting a specific code area and comparing its documentation with the implementation; done should mean the documentation is up to date for that scoped area.

Written by the indexing model from the issue text.