I'm currently running
bitcoind -testnet. I ran
bitcoin-cli dumpwallet ~/wallet-output just to explore the output and it looks like it created 102 private/public key pairs that I assume are just sort of pre-generated just for the convenience of having them on hand.
However, I'm surprised they all seem to be somehow "recognized" as part of the testnet blockchain already, even though they've never been used. For example, when I search for one of these addresses in Block Explorer I see an address with zero transactions and a 0 BTC balance: https://testnet.blockexplorer.com/address/mxwDTWg556BDzZhEWvJ1EeYwSYxG42wKZC. This is different from addresses I've created "outside" of the bitcoin tools (e.g., https://www.bitaddress.org). For example, Block Explorer "can't find" this address: 1XitCFAkFhNR6PoJsPcxjsFzkMegx4Ky5. I would expect that to happen to all of the addresses pre-generated in my wallet until I actually use them.
bitcoind "register" these addresses on the testnet blockchain? And how exactly did it do that? Is that a special transaction type?