What is a gcf file and how do I open a gcf file?
A game cache file integrated with encoding specifications and compression standards developed for the GCF format are used for the online distribution of different Steam game versions. These Steam game versions are video games developed by Valve, which also created the GCF format. These GCF files are affixed with the .gcf extension and contain data like checksums and fragments of files associated to a particular Steam game version or update. Metadata details associated to a specific Steam game installer or update is also entered by Valve developers as part of a GCF file's content. The Valve distribution service hosts these GCF files in their Web servers, which means quick and easy download and update access for Steam users. As the name of the GCF file format suggests, "GCF" stands for Game Cache File", though originally, "GCF" stood for "Grid Cache File". Valve Steam games and updates have, as of this writing, versions for Mac platforms. Users of computers running on Microsoft Windows-based systems can on the other hand play these Valve Steam games by downloading and installing these GCF files.
Relevant gcf file links:
How to open gcf file on YoutubeHow to open gcf file on Wikipedia
How to open gcf file on Microsoft.com