What does the dashed redline actually mean?

This is an automatic. Most of the time when I floor it, the car will go to 6,500 going past the dashed redline but other times when I floor it, it’ll only go to 6000 rpm before shifting. I’ve always wondered what the dashed redline is. This is a ford fiesta.

This is an automatic. Most of the time when I floor it, the car will go to 6,500 going past the dashed redline but other times when I floor it, it’ll only go to 6000 rpm before shifting. I’ve always wondered what the dashed redline is. This is a ford fiesta.