The link you provided appears to be an API endpoint for the mempool.space block explorer, specifically for accessing the hex data associated with a particular Bitcoin transaction.

When you send a Bitcoin transaction, it is initially included in the mempool, which is essentially a pool of unconfirmed transactions waiting to be added to the next block in the blockchain. By accessing the hex data associated with a particular transaction, you can view details about the transaction, such as the amount of Bitcoin being transferred and the addresses of the sender and recipient.

API endpoints such as the one you provided can be a useful tool for developers and researchers who are looking to analyze and study the Bitcoin blockchain. By providing direct access to the underlying data associated with Bitcoin transactions, API endpoints can facilitate the development of new tools and applications that can help make Bitcoin more useful and accessible to a wider range of users.