I know each node has its own mempool for transactions to be mined. My question is, for those unconfirmed transactions shown in the block explorers, are they in the explorer's own mempool, or they can also be transactions from other nodes' mempool?
If one transaction has been on Chain.so for 24 hours but not on other explorers, does it means that this transaction is created by Chain.so, and Chain.so has not broadcast this transaction into the network?