Links that point to non-existent pages when served via Parsoid e.g. https://en.wikipedia.org/api/rest_v1/page/html/Facebook
<a rel="mw:WikiLink" href="./Title" title="Title" id="mwrA">Title</a>
with no meta data explaining they are red links.
If mobile is to use Parsoid it will need to work this out in some way to avoid sending users to blank pages unexpectedly.