Current.gpx file: Function? Purpose?

[Peobody]

I was looking inside my Current.gpx file yesterday and within its content I saw a route name whose route does not appear in the XT's list of importable routes. That route only existed on the XT in the form of a .trip file. I also noticed that the modified time stamp of the Current.gpx file coincided with power-up of the XT, in this case via USB connection to my laptop.
Can anyone tell me...
... what exactly is the purpose and function of the Current.gpx file?
... what is happening during XT start-up that modifies the Current.gpx file?
--- if writing a .trip file directly to \.System\Trips could result in information about it being added to Current.gpx by the XT?

[sussamb]

current.gpx is simply a one way copy of what is in inaccessible, to the user, memory that your device uses and which is available via its menus.

current.gpx is written on start up if there has been a change. You can prove this by deleting it then restarting your device.

The purpose of that file is to allow programs like BaseCamp to access your data.

[Peobody]

Thanks @sussamb. That helps. I was erroneously thinking that Current.gpx contained data for importable routes. Your response helped clear the fog. Routes available for import are ones the XT finds by searching temp.gpx and all other .gpx files in the \GPX folders in internal storage and on the SD card.