nix/doc/manual/rl-next/rfc4007-zone-id-in-uri-rfc6874.md

synopsis	prs
Represent IPv6 RFC4007 ZoneId literals in conformance with RFC6874	13445

Prior versions of Nix since #4646 accepted IPv6 scoped addresses in URIs like store references in the textual representation with a literal percent character: [fe80::1%18]. This was ambiguous, because the the percent literal % is reserved by RFC3986, since it's used to indicate percent encoding. Nix now requires that the percent % symbol is percent-encoded as %25. This implements RFC6874, which defines the representation of zone identifiers in URIs. The example from above now has to be specified as [fe80::1%2518].