It has a eMMC sodered on Solid stade drive, there are models with 16GB or 32GB disks. The latter one beeing a little bit more rare. But, it does have a SD-card slot that supports storage extension, but probably not the answer you're looking for. I've been looking into a possible mother board swap that would work in the stock enclosure, or at least with some modification but i haven't come to find anything suitable yet since i live in the EU and customs for every motherboard that might be compatible (at least physical) gets more than economically viable to order from the US.

There's often a QR with a code written on the same label, that doesnt seem to be there on a third party LCD (or assemblys) and theres always a Apple OE number on the back side of the Tcon board approx area were the FPC connector sits on the forward facing side on the TCON board, here's more about compability; https://logi.wiki/index.php/MacBook_LCD_...