This is the other history: the same chain id, different blocks. The RPC serving this page is named under the head. The other fork nodes stay in the menu.
Search transactions
This search reads only the node serving this history. A transaction hash is one lookup. An address search checks a recent window of blocks and shows the matches from that window.
Reading this history
Checking the other history. The chain id is the same and the blocks are different. The preferred endpoint is used while it stays within 8 blocks of this history.