Roblox has supported ZSTD compression on chunks for a while now by checking for the magic number (0xFD2FB528) on the start of compressed data.
I have made a patch on my end using github.com/klauspost/compress/zstd but due to my limited knowledge of Go I don't feel like it's adequate for a pull request.
But I have attached an example file using ZSTD compression for testing.