It is often useful to be able to create HTML links to external resources. For example, here the value of the href attribute will be set to the value of the tiddler MyLinkDestination:

<a href={{MyLinkDestination}}>link</a>

However, there is an unexpected security issue that means that most of the time the link should have the rel attribute set to noopener noreferrer to maintain privacy of the URLs of private TiddlyWiki's (eg on Dropbox). See https://mathiasbynens.github.io/rel-noopener/ for more information.

<a href={{MyLinkDestination}} rel="noopener noreferrer">link</a>