The Preload Fonts setting is for locally, or CDN-hosted fonts only.

However customers are trying really hard to preload external fonts :)

Steps to reproduce

• Enter: fonts.gstatic.com/s/poppins/v13/pxiByp8kv8JHgFVrLGT9Z1xlFQ.woff2

• This does not get santized correctly and instead of being removed, it becomes:
  /fonts.gstatic.com/s/poppins/v13/pxiByp8kv8JHgFVrLGT9Z1xlFQ.woff2

• /fonts.gstatic.com/s/poppins/v13/pxiByp8kv8JHgFVrLGT9Z1xlFQ.woff2 can also be entered directly and it is saved as-is.

• On the front end of the site, this results in:
  https://www.example.org/fonts.gstatic.com/s/poppins/v13/pxiByp8kv8JHgFVrLGT9Z1xlFQ.woff2

Backlog Grooming (for WP Media dev team use only)

• Reproduce the problem
• Identify the root cause
• Scope a solution
• Estimate the effort