This is the DC equivalent of JRACLOUD-77014

At present there is no way to filter the issues created via incoming Mail handlers. This is because there are no fields associated with issues that differentiate them as created via mail handler OR through the portal.

Customer's request: It will be helpful to be able to fetch this information using JQL OR it would be great if the information that the issue was created via an incoming Mail handler, is seen in the history of the ticket.