Function is_root_relative_link 

pub(crate) fn is_root_relative_link(text: &str) -> bool

Returns whether the text represents a root-relative link. These look like /this and are resolved relative to a base URL’s origin. This can also be called “domain-relative URL” (by MDN) and “path-absolute-URL string” (by WHATWG). From MDN:

Domain-relative URL: /en-US/docs/Learn_web_development — the protocol and the domain name are both missing. The browser will use the same protocol and the same domain name as the one used to load the document hosting that URL.