Yep! This is a DDC; if you look into the hexadecimal folders inside Content you’ll see a bunch of UDD files. This DDC isn’t very large compared to Compressed.ddp, which I suspect contains a lot more different sets of compiled shaders given its size, nor does it generally have the hit rate, but it seems to be required.
The only solution for now is to let the engine regenerate it, then copy the whole folder somewhere you’re confident it won’t be deleted and change the global shared DDC path to point to it.