At anytime, you can view the KML source of items in the Places panel. To do this, select the item and click Edit > Copy. In a text editor, click Edit > Paste. The KML source appears in the new document.
Personally, I use this method to examine the source of Places data I've come across that show content in an interesting way. You can also examine the source of Layers content by right clicking (CTRL + click on the Mac) a point of interest in the 3D viewer, saving it to My Places and then use the method described above.