Is there any testnet block explorer or something where I can see how Bulletproofs transactions are? I'm having problems parsing a transaction and I can't figure out if it's a bulletproof transaction or not.
The best way to do so is to use:
monero-utils-deserialize --input <hex dump goes here>
This will parse and tell you what it is.
This tool is only built in debug mode as it is a debugging helper.
Note that Bulletproof format changed on testnet, and the network was reorganized from the start of v7, so you might have an old style proof, which will fail to parse.
To see if a given transaction is in the current chain (from its transaction ID), run this in monerod:
print_tx TXID +json
You can also checkout a testnet explorer at testnet.xmrchain.net.