So, I've spent the past week working on our web-based UI. However, my changes were causing the UI to render completely blank.
These changes involved consolidating #webpack bundles.
Heedlessly, a few weeks ago, I changed my local config to use our CDN. See the problem?
The server was sending a file to me which only had half of the code needed. So, of course, it bugged out.
Moral of the story: Be aware of your config files and how they might impact your local development.