Add domain/host specific settings
Just an idea... (sub)domain specific config options. E.g. you have certain client certificates for single hosts without the need to specify those on the command line. Same goes for proxy settings, pinned keys, --secure-protocol etc.
Format: we just have multiple keys (domain/subdomain) each having a list of options. We could simply extend the 'wgetrc' syntax to accept 'sections' like
[.example.com] with a default to an all-matching wildcard
[.]. That is backward-compatible.