That's kind of a weird situation. The 2015 Shield codes floating around actually came from a Harmony originally which, in turn, were learned from an Nvidia IR remote. So you should be able to find Nvidia Shield in the database. However, if you check the compatibility page, it appears that they've replaced the Shield IR codes with the Bluetooth version of the device which of course won't work on IR remotes like the 900. So I can't really confirm whether they're still there or not. I can tell you that the native Shield IR codes are not the same as MCE or Xbox or anything else like that. They are entirely unique (NEC1 129.126, OBC 2-69).
Regardless, if you strike out, I can send you the pronto hex for the 2015 Shield native IR, and you can email to Logitech to add to your account.
Regardless, if you strike out, I can send you the pronto hex for the 2015 Shield native IR, and you can email to Logitech to add to your account.