It would be nice if we could set that every new user created via mail handler will have the username stripped starting from '@'.

Nowadays, whenever a user is created through a mail handler, the username of the user become automatically his email address.

For instance, if I have my mail handler set to create new users upon incoming emails and my email is user@atlassian.com, my username in JIRA will be 'user@atlassian.com'. With this improvement, my username will become 'user'.