While we can verify that a transaction was mined using a library and Clarity's built-in functions, as outlined in the Verifying a transaction on the BTC chain docs, we can parse a Bitcoin transaction using Clarity as well.
This doesn't actually require having access to the chain, all we need is the raw transaction hex.
If you aren't familiar with how Bitcoin transactions are encoded in raw form, take a quick look at that.
The short version is that all of the data from a Bitcoin transaction is encoded in hex form in a string of numbers, we can slice out pieces of that hex value to pull out all of our transaction data.
The process to do this is relatively complex, but the Clarity-Bitcoin library comes with a function called parse-tx that makes this simple.
All we need to do is pass it a raw transaction hex and we can get back the data of the transaction, including inputs and outputs.
:::caution Note that currently the library only supports legacy transactions, although work to support segwit and taproot transactions is currently underway. :::