I'm preaching through Matthew, and it just occurred to me that it would helpful to have parallel passages marked out in the Gospels (and other places as well). The links could go next to the passage title, with the current passage marked out in some way. Yes, I know that I can just hover over the footnote, but this would (a) make it clearer when there are parallel passages, and (b) make it that much easier to navigate. I've mocked up what I imagine it could look like:
