It's getting downloaded from a 3rd party because those 3rd parties are behind the Great Firewall in china. Without those local caches the xcode download can so

It's getting downloaded from a 3rd party because those 3rd parties are behind the Great Firewall in china. Without those local caches the xcode download can sometimes take days or never finish at all. Downloading from a 3rd party is fine IMO (after all the internet is just a big game of whisper-down-the-lane), but verifying checksums and signatures is incredibly important.