An inline external link in square brackets and without a title doesn't appear in Flow pages on mobile web. For example - "[http://www.howdoeshomeopathywork.com/]"
To see it in action: This first post in this Topic is supposed to have a visible and clickable  link, but it doesn't: https://m.mediawiki.org/w/index.php?title=Topic:Se6vfq581nl12yuz&topic_showPostId=se6vfq6wugjba8sb#flow-post-se6vfq6wugjba8sb
In the same post on desktop you can see "": https://www.mediawiki.org/w/index.php?title=Topic:Se6vfq581nl12yuz&topic_showPostId=se6vfq6wugjba8sb
It also appears on a non-Flow wiki page: https://m.mediawiki.org/wiki/User:Amire80/mobile_link