Root issue:
TL;DR When users are prompted to log in to phabricator, there is a confusion as to which username to use. As a result, they will often try several usernames with different passwords before either locking their user out, giving up or (hopefully) gaining access.

Background We're in the process of migrating from several legacy internal LDAP auth providers to a new one. As part of this, we've switched our phabricator instance over to the new one. This new one uses various different standards for defining usernames. Unfortunately, the new system has been imposed by a central IT team, and is not something we have the influence to change.

Request:
I'd like the ability to display an (optional) line of text on the login page that we can use to prompt users to attempt the correct username format (and password combo) first time. This would help alleviate frustration amongst our users.

An example implementation of this is here: https://docs.mattermost.com/administration/config-settings.html#login-field-name