myTracks manages the tracks on its own. That means it has an own library where the files are stored. It is not indented that the user directly accesses these files. Nevertheless, sometimes it is important or interesting to know where myTracks stores these files.
Up to myTracks 2.3.10 all the GPS tracks and some other files are stored at the following location:
/Users//Library/Application Support/myTracks
Due to the sandboxing, that was introduced with myTracks 2.4.0, these files are located here:
/Users//Library/Containers/info.stichling.myTracks/Data/Library/Application Support/myTracks
Note: Sandboxing is not available with OS X 10.6 Snow Leopard. Therefore on Snow Leopard the files are still located at the location mentioned first.