There are two error files in this theme, one for 404s and one for all other errors.
This file is the latter, and handle all 400/500 errors that might occur.
Because 500 errors in particular usuall happen when a server is struggling, this
template is as simple as possible. No template dependencies, no JS, no API calls.
This is to prevent rendering the error-page itself compounding the issue causing
the error in the first place.
Keep this template as lightweight as you can!