Checkpoint (block category)

A checkpoint is a type of non-solid foreground block that replaces the player's previous spawn position (being the Main Door or a previous checkpoint) upon the player walking over it. If the player respawns or dies they will return to the last checkpoint they walked over.

After going through a Race Start Flag and then through a Race End Flag, all checkpoints will be reset and the player would respawn at the white door on death. The same goes for the Challenge Timer and /kick, /kickall command.