BUG?: HTML files are big

[larsoner]

Waiting for CircleCI to upload artifacts, I noticed:

Uploading /home/circleci/project/doc/_build/html/generated/mne.chpi.head_pos_to_trans_rot_t.html (107 kB): 

locally, it looks like ~80 kB is in a <ul> with ~3k lines of the form:

   <li class="toctree-l2">
    <a class="reference internal" href="mne.io.anonymize_info.html">
     mne.io.anonymize_info
    </a>
   </li>

Looks like this is really the full left column of collapsible API pages.

@drammock have you thought about how this could be optimized at the pydata-sphinx-theme end? We have ~500 of these docs so we are talking about something like 50MB of redundancy in content around these pages, all of which is identical except for which are collapsed/shown (which is maybe easy to take care of in JavaScript?). Maybe it's not worth worrying about, in which case feel free to close.

[drammock]

This is a known issue upstream. I haven't followed the discussion too closely but I'll look at it again and see what, if anything, can be done about it

[larsoner]

No rush, good for a Sunday hack! Closing as an upstream issue.

[drammock]

Here are the possibly relevant issues / guidance for reducing TOC size within the theme. I haven't re-read all of these recently, just collecting them here as a breadcrumb for whenever I or someone else has time to fix this. TLDR: it probably involves either limiting TOC depth with a theme setting, or suppressing (via path/wildcard) certain TOC entries from showing up at all (regardless of their depth).

• Slow page builds in 6.0 when generating navigation bar pydata/pydata-sphinx-theme#381
• Expandable sidebar sections with huge sphinx sites (eg large API reference) results in a very slow build pydata/pydata-sphinx-theme#364
• https://pydata-sphinx-theme.readthedocs.io/en/latest/user_guide/configuring.html#navigation-depth
• https://github.com/executablebooks/sphinx-remove-toctrees