Following the LAN7515 link from that page takes one to a generic Microchip home page, which provides no details on the LAN7515. The LAN9514 link works as one would expect.
I and others have been looking for an actual LAN7515 datasheet but nothing has turned up yet. Someone here reported that it had been asked about on the Microchip forums but I could find no sign of that, so either it wasn't, those posts have disappeared, or are not appearing in search results. And I couldn't find them when manually checking forum posts.
BobKruse above. Seems I was reading page 1 thinking that was the last and latest page of the thread
Perhaps BobKruse could update us on his post to the forum.
Though Microchip say the chip is in production, it is not available for on-line purchase, and although references to LAN7515 do turn up in search results, none of the pages or documents linked to which I followed actuallyreference the LAN7515. Search results suggest it was known about in June 2017 so it is all rather odd.
The only page which appears to give any detail on the LAN7515 is the comparison page pointed to, and that just gives headline specs, certainly not enough to allow a design using it to be developed.