The fetch a transport issues. An embedder replaces it to add its own
credentials, to route through a proxy, or to serve a package from a local
store; the policy below still applies to whatever it returns, so a
replacement can narrow what is reachable but never widen what is accepted.
The fetch a transport issues. An embedder replaces it to add its own credentials, to route through a proxy, or to serve a package from a local store; the policy below still applies to whatever it returns, so a replacement can narrow what is reachable but never widen what is accepted.