The "What links here" tab is available again on the various content pages. It shows a list of other pages that link to them.
I use it most often with Person pages. As new diary pages have been added to the site I've linked any mentions of a person to their page. Then we can use "What links here" like an index in a book.
e.g. here's the page for Brian Fay: https://gwulo.com/node/11517
Then if you click the 'What links here' tab, you can see a list of the diary pages that mention him: https://gwulo.com/node/11517/whatlinkshere