Similar to Whonix website security rating - "B" (Mozilla Observatory) - Content Security Policy (CSP) - #21 by Patrick.
Browsers don’t support permission policy yet and there’s no documentation (that I understand with reasonable time spent) on how to use it.
Quote Permissions-Policy - HTTP | MDN
Feature-Policy
Experimental
This is an experimental technology
Check the Browser compatibility table carefully before using this in production.Warning
The header has now been renamed to
Permissions-Policyin the spec, and this article will eventually be updated to reflect that change.
Once that changes, I will look into it. Waiting for major browser supporting and documenting that such as Mozilla MDN.