what is the best channel for making suggestions as to changes to ubuntu (or more specifically ubiquity)? i have spotted an issue that is not really a bug, but its a fairly big usability hurdle.

I was helping somebody install ubuntu on a vm, and they kept getting stuck at the 'Who are you' section, eventually i spotted that they had an uppercase letter in their username.

The problem is that the installer did not let them know this was the issue, and it was very frustrating for the user.