Originally, I had the idea that any knowledge of the outside world is
forbidden knowledge but I have since decided (and written with the
assumption) that people generally know of the outside world but regard it
as completely uninhabitable.
The index doesn’t have to be a PHP file since there is no need to
generate the list of chapters anew every time the ToC is opened.
Instead, the list of chapters is generated once, ahead of time, and
saved to the index.html.
As an added bonus, this allows the ToC to be generated and used
as a local file.
BodgeMaster