What is a reboot card?

When you are killed in Fortnite Chapter 2, a reboot card is dropped at the location that you died. Another player can then try to grab that reboot card, before it expires, and then take it to a reboot van which are located all over the map. The map will show the location of team players that are dea and can be rebooted, and if you get the reboot card, the location of the reboot van.

Once you get the reboot card, there is no time limit to when it can be used.