Tracker consists of a profile and a task that create KML files that Google Earth can display.
The first time the ToggleTracker task is run, it creates a file named Track_%DATE_%TIME.kml in the Tasker/tmp folder, writes a KML header to that file, then enables the NewFixAvailable profile.
The second time it is run, it disables the NewFixAvailable profile, then writes a KML trailer to the file.
The profile, NewFixAvailable, writes a new KML placemark to the Track file when a new track position update is available, triggered by a change to %LOCTMS, provided that there hasn't been a track position update for 10 seconds. Each position is labeled with the date and time (hh.mm.ss). The KML description of the position (the text that shows when you click the yellow pushpin in Google Earth) consists of the following:
Acc:%LOCACC Prv:%LOCPRV Spd:%LOCSPD Alt:%LOCALT /
If you create a widget for ToggleTracker, you can start and stop tracking from your home page.
To view a KML file that Tracker creates you can either:
*view it in the Google Earth Android apo
*upload it to your desktop and open it with Google Earth.
*upload it to the web, and put the URL to the KML in the search box of Google Maps (http://maps.google.com/). This still only works on a desktop computer, but allows the viewing of a kml or kmz file without installing Google Earth.
*several other tools exist for publishing kmz files (e.g. Google Fusion Tables, http://geocommons.com/ etc.)
I'll be monitoring this Tasker thread for a while if you have any questions.