Is the raw Monero blockchain file different for Linux, Windows, or Mac?
Where can I download it?
The .raw file is "raw" as the name implies, meaning it should be platform-agnostic, ie, the data inside is the bare minimum, unoptimized, blockchain data, as it flies over the network, and nothing else. Think of it as just copying and pasting block data one on top of another and saving this into a file. The .raw file, then, is just a collection of all the blocks in the correct sequence.
Even before v.0.10.0 you could import it using the tools available.
When importing, the wallet needs to check it for consistency, by validating each block in the .raw file against concensus rules, because it can't know whether it had been constructed in the correct way, so it needs to check the signatures, PoW etc., unless you exported the .raw yourself or got it from a trusted source.
You can download it here. The simple structure means also that if it gets updated on the site, you can add the difference on top of the file you had downloaded in the past, without having to download from scratch. I did this using the wget tool:
wget --continue --output-document=blockchain.raw https://downloads.getmonero.org/blockchain.raw