@Shinhan7 said:
Minecraft uses Anvil files and NBT format.
Both obfuscation and compression are mentioned in couple places, so it very well might be he's reading it wrongly.
There's no obfuscation in any saved NBT data, and the only compression is that the entire file is gzipped.
More likely is that he's parsing lists wrongly, given that all the compound tags with broken names are directly inside list tags.
(Also the correct name for tag 0x0A is "compound", not "struct")