It would be of use to be able to link to a specific change of any given diff, especially in the case of a complex diff. For example, in this diff between two versions of the article "Wikipedia" on the English Wikipedia that I selected at random:
the sentence "Also, all pie-charts may be displayed properly in desktop view, but not in mobile view." has been added to the article at what was previously line 449. If I want to direct someone to that particular change, I need to instruct them to either scroll down to the "Line 449" indicator or search for the text in question. This is inefficient.
So, I suggest that every change in the diff (displayed with a "+" or "-" indicator) is accompanied with an anchor link (preferably using an icon of the chain type commonly used online for permanent links). These would be simply calculated as integers starting at 1.
Let's pretend that in the case of the example above, the change I refer to was the 56th in the diff (it wasn't - actually counting what it was would take a long time). An anchor link for that change would generate the following URL: