In-Group List ID
If IN_GROUP is selected as the DID Route, then this is the List ID that leads may be searched through and that leads will be inserted into if necessary.
In-Group Entry List ID
If IN_GROUP is selected as the DID Route, then this is the Entry List ID that a new lead will be populated with if a new lead is added. Default is 0 for disabled.
Does the second field override the first one? I would suggest updating these help texts so it's clear how these fields work together.
In the manager manual it says additionally for the In-Group Entry List ID:
(This feature has to be enabled in Admin → System Settings).
And in System settings it says:
Enable DID Entry List ID
This setting if enabled will allow a manager to define an entry list id to use on the DID modify screen. Default is 0 for disabled.
My confusion is that the In-Group List ID field is also used for inserting new leads into a list.