The Messages List is the second tab in the Status Information Window (menu item
Plugin > LiveTraffic > Status / Information...):
Above the list you can select which message level is shown and you can do a full-text search in all the messages.
The colors are the same as used in the Message Area, see there.
Sort by any column by left-clicking on the column's header.
Change the order of columns by dragging the column header.
Select visible columns by right-clicking on the column header an selecting the columns from the pop-up menu. The following columns are available:
Your local time the message was generated
X-Plane's "Network Time" of message creation. This is the amount of time since X-Plane startup (synchronized across several X-Plane installations in your network if you have them)
The severity level of the message: Debug, Message, Info, Warning, Error, or Fatal. See Message Area for more details.
Detailed source code location where the message was generated.
(This columns are hidden by default.)
The actual message text.