.PPTHTML File Extension
File TypePowerPoint HTML Presentation
File format categories include Binary, Text, XML, and Zip. The format of this file type has not been determined.
What is a PPTHTML file?
HTML version of a .PPT file created with Microsoft PowerPoint, a program used for creating presentations; contains HTML that can be used to display the presentation with formatting similar to the original PPT file; used for viewing published presentations in a Web browser.
PowerPoint no longer supports PPTHML files. If you want to publish or share a presentation, you should use the broadcast features in PowerPoint 2010.