I know what the apple touch icon is, and I have seen an apple desktop before, so I can imagine what it would look like. I also know how to add an apple touch icon to my site.
But here's the burning question: I keep getting (failed) requests for this touch icon... So what does that mean?
Was an apple user simply accessing the site? Were they bookmarking it?
What is the action from an apple machine that triggers the request for the touch icon?
When somebody using an iOS device visits your web-page and decides to "bookmark" your page by addding your page to their Home screen the apple touch icon is used. It is like a favicon for browsers but has higher resolution and "might be designed" to match app icons ...