Firefox warning: Content Security Policy: Couldn’t process unknown directive ‘require-sri-for’

Why does Firefox tell me

Content Security Policy: Couldn’t process unknown directive ‘require-sri-for’

when Mozilla’s documentation says they’ve implemented it?

The meta tag Firefox is complaining about:

<meta http-equiv=”Con… Continue reading Firefox warning: Content Security Policy: Couldn’t process unknown directive ‘require-sri-for’