From MusicBrainz Wiki

Official Relationship Type Whitelist

Attention.png [[{{{whitelistSource}}}]] is subject to special rules regarding what sites may and may not be linked.

Only those sites which have been whitelisted may be linked to. A link to any site not on the whitelist is not permitted.

  • Any edit to add a link to a site not on the whitelist should be voted down.
  • Any such link which has somehow already been added should be removed.

The official whitelist for this relationship type can be found [[{{{whitelistPage}}}|here]].