The empty-string value for SVG specifies no referrer policy, causing a fallback to a referrer policy defined elsewhere, or in the case where no such higher-level policy is available, falling back to the default referrer policy.

""

no-referrer

no-referrer-when-downgrade

origin

origin-when-cross-origin

same-origin

strict-origin

strict-origin-when-cross-origin

unsafe-url

World Wide Web Consortium (W3C)