Username error message on create account is not clear

When creating a new account and if the username dont use the common pattern you receive an error message <<Handle must have only letters, numbers or hyphens >> in the first place i didn’t understand what the handle is, so i had to try to change the password then the username, i suggest to change the error with <<Username must have only letters, numbers or hyphens >>

Is this creating a forum account? An Exercism account? Or is this referencing a specific exercise? Is handle a technical term called out in that exercise?

I recognize that error message from Exercism’s account signup process when I was testing something unrelated a while back.

Ah. I see. I found a similar test message in the website test code.