Profiles - Pre Field and Post Field Help
The pre- and post- field help areas will have identifying CSS classes from CiviCRM 4.7.

This was the issue: https://issues.civicrm.org/jira/browse/CRM-16328

And here's the patch / PR if you want to apply it to your current version of CiviCRM: https://github.com/civicrm/civicrm-core/pull/5667