6 uses of USERNAME_MAX_LENGTH

user_account_form in modules/user/user.module
Helper function to add default user account fields to user registration and edit form.
user_login in modules/user/user.module
Form builder; the main user login form.
user_login_block in modules/user/user.module
user_pass in modules/user/user.pages.inc
Form builder; Request a password reset.
user_validate_name in modules/user/user.module
Verify the syntax of the given name.
_install_configure_form in includes/install.core.inc
Form constructor for a site configuration form.

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