Fetch directive

CSP fetch directives are used in a Content-Security-Policy header and control locations from which certain resource types may be loaded. For instance, script-src allows developers to allow trusted sources of script to execute on a page, while font-src controls the sources of web fonts.

All fetch directives fall back to default-src. That means, if a fetch directive is absent in the CSP header, the user agent will look for the default-src directive.