As visible at https://www.mediawiki.org/wiki/Topic:Sdoatsbslsafx6lw , Flow shows all links as if they were internal links:
- external links have no icon, no classes and no nofollow,
- interwiki wikilinks don't have their class="extiw" either and hence are blue rather than light blue.
This can cause unwanted dofollow links (links without nofollow) against our policies (see T54617: Respect $wgNoFollowLinks and $wgNoFollowDomainExceptions and T68289: A16. Flow: external links should have rel="nofollow" property), as well as a style inconsistency for interwiki links.
Examples:
<a rel="mw:ExtLink" href="https://phabricator.wikimedia.org/T90788" title="phab:T90788" data-parsoid='{"stx":"simple","a":{"href":"https://phabricator.wikimedia.org/T90788"},"sa":{"href":"phab:T90788"},"isIW":true,"dsr":[835,850,2,2]}'>phab:T90788</a> <a rel="mw:ExtLink" href="http://flow-tests.wmflabs.org/wiki/Testwiki:Support_desk" data-parsoid='{"stx":"url","dsr":[919,975,0,0]}'>http://flow-tests.wmflabs.org/wiki/Testwiki:Support_desk</a>
Note, when we convert to RESTBase (T94574: Switch Flow from ExternalStore to RESTBase) there will probably have to be (and if not, could be) a one-time reconversion of all our Parsoid HTML. Also, at that point, there may be a standard process for updating HTML should the Parsoid rendering change for things like this.