Before you reach the checkpoint, it allows you to test out and jump to that point if you pass the test. After you've passed it, it no longer has any meaning or function.

The checkpoint before you pass it is orange (I think) and it says Test out of x skills. Once you pass it it turns grey and just says Checkpoint. After you have gone past the checkpoint you cannot test out of it again. It is not that important what it is called after it has been passed. The number of total checkpoints varies with the language, Italian has 4 and I think Spanish has 3.

Thanks to both of you!

Got it. Thanks. They should consider lighting the checkpoints up after the foregoing lessons have been completed.