What is revert back?

"Revert back" is a redundant phrase, as the word "revert" already means to return or go back to a previous state. Therefore, it is more accurate to simply say "revert." Using "revert back" can be considered poor grammar, and can cause confusion or annoyance for some readers or listeners. Instead of using this phrase, it is recommended to simply use "revert" to convey the intended meaning.