It seems that when I paste the following into the editing area
<a href="#the-columbo-approach">The Columbo Approach</a>
<a href="[#the-columbo-approach](#the-columbo-approach)">The Columbo Approach</a>
which seems a bit strange.
I also tried to copy links from the right hand TOC to create internal links though it seems the TOC on the right does not contain elements one can copy from.