You can find the documentation for that call, such as it is, here. It's not very helpful.

I can give you a few tips, though.

• n is the vout of the input. A vout plus a txid unambiguously specify a transaction output, and are collectively known as an outpoint. More.
• tx_index is a field used by blockchain.info, and has no meaning outside of blockchain.info's api.
• No idea what type means. Looking at a few transactions at random, it always seems to be zero.