.HTML5 File

The html5 file extension is occasionally used for fifth revision of the HTML standard, which is a a core technology markup language of the Internet used for structuring and presenting content for the World Wide Web.

However, the standard extension for HTML5 is html file extension.

How to open:

Any text editor can open and edit these files, whilst web browsers probably can view these files only if the extension is HTML.

How to convert:

Various conversions are possible, depending on what you want to do with the HTML5 file.