Check out this guide on launchers and desktop files.
Unity Launchers are actually files stored in your computer, with a '.desktop' extension. In earlier Ubuntu versions, these files were simply used so as to launch a specific application, but in Unity they are also used so as to create right-click menus for each application, which you can access from the Unity Launcher.
The lines in the file are basically instructions for your desktop environment on what to do with the application/launcher when clicked on or launched from that .desktop file. For example, the "Exec=..." line is an instruction to execute the command that follows the "=" char.
You should be able to open the files with vim, nano, gedit, or just about any text editing program.