A big mapping url schemes to their protocols' default ports. See comments below for notes. Painstakingly assembled by crossreferencing https://www.iana.org/assignments/uri-schemes/uri-schemes.xhtml and https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml

scheme_port_map.json

{
  "acap": 674, 
  "afp": 548, 
  "dict": 2628, 
  "dns": 53, 
  "file": null, 
  "ftp": 21, 
  "git": 9418, 
  "gopher": 70, 
  "http": 80, 
  "https": 443, 
  "imap": 143, 
  "ipp": 631, 
  "ipps": 631, 
  "irc": 194, 
  "ircs": 6697, 
  "ldap": 389, 
  "ldaps": 636, 
  "mms": 1755, 
  "msrp": 2855, 
  "msrps": null, 
  "mtqp": 1038, 
  "nfs": 111, 
  "nntp": 119, 
  "nntps": 563, 
  "pop": 110, 
  "prospero": 1525, 
  "redis": 6379, 
  "rsync": 873, 
  "rtsp": 554, 
  "rtsps": 322, 
  "rtspu": 5005, 
  "sftp": 22, 
  "smb": 445, 
  "snmp": 161, 
  "ssh": 22, 
  "steam": null, 
  "svn": 3690, 
  "telnet": 23, 
  "ventrilo": 3784, 
  "vnc": 5900, 
  "wais": 210, 
  "ws": 80, 
  "wss": 443, 
  "xmpp": null
}

schemes_without_netloc.json

[
  "mailto", 
  "about", 
  "sip", 
  "tel", 
  "data", 
  "urn", 
  "bitcoin", 
  "pkcs11", 
  "magnet", 
  "blob", 
  "sips", 
  "news", 
  "geo"
]

@pgroke-dt, just seeing this, and while I think this might be too small an artifact to be copyrightable per se (facts are not copyrightable), if it eases anyone's concerns further, I'm happy to say that the contents of this gist are licensed CC0.

Also, in addition to boltons, the mapping is available in hyperlink as well. :)

Yes, you're probably right re. being non copyrightable. I think your comment here should be enough in case anyone has concerns. Thanks :)