Who are the 20 hostages being released?

BBC:

The Israeli military says the first hostages have been handed over by Hamas, ahead of the expected release of 48 captives – 20 of whom are believed to be alive.

All but one were among the 251 people abducted during the Palestinian group’s attack on southern Israel on 7 October 2023, during which about 1,200 other people were killed.

Israel responded by launching a military campaign in Gaza, during which more than 67,000 people have been killed, according to the territory’s Hamas-run health ministry.