How to open Data in Keyhole Markup Language for Google Earth .kml files
Have you had trouble opening the kml file on your computer? What are kml files? We explain what they are and recommend software that we know will open them.
What is kml file?
Navigation/map files saved in Google's KML (Keyhole Markup Language) file format typically have a kml extension.
Data in Keyhole Markup Language for Google Earth description
KML (Keyhole Markup Language) is a file format used to display geographic data in an Earth browser, such as Google Earth, Google Maps, and Google Maps for mobile.
KML uses a tag-based structure with nested elements and attributes and is based on the XML standard. KML files can contain a variety of geographical data like points, lines, polygons, images, text, and more. This data can be used to mark locations, create paths, provide descriptions, and even animate the view of the map.
The KML file format is an open standard, meaning it can be used and implemented by anyone without restrictions. It was originally developed for use with Google Earth, which was initially named Keyhole Earth Viewer.
Suggested software to open kml file

Google Earth
A virtual globe, map and geographical information application by Google

Google Earth for Mac
A geographical information platform
There are other KML filename extensions with the same .kml suffix
kml - Hiebook e-Book
A kml file extension is related to the Hiebook e-Book format. Probably obsolete.
kml - HP 48 emulator Win48 script
A kml file extension is related to the Win48, an emulator of HP 48 calculator. A kml file stores script.