see https://docs.moodle.org/37/en/MathJax_filter

> The MathJax filter is enabled by default

> The MathJax filter works without any additional configuration (using the MathJax Content Delivery Network)

Problems with this:

• Privacy issues; The CDN gets the referrer (there is no referer policy set at the 2 instances which know) + CDN gets time + amount of activities per IP address + ...
• dependency on external services

Most admins do NOT know about the default + the consequences it has

Two possible solutions:

• don't use a CDN by default
• add a big scary warning about this default in the setup instructions