User Configuration > Administrative Templates > Microsoft Office 2016 > Web Archives
User
HKCU\software\policies\microsoft\office\16.0\powerpoint\internet
"All browsers": Save new PowerPoint web pages in a format that is compatible with all browsers. | "Windows Internet Explorer 4.0 or later": Save new PowerPoint web pages in a format that requires Windows Internet Explorer 4.0 or later. | "Based on installed browsers": Examine the browsers installed on the user's computer and save new PowerPoint web pages in the smallest possible format that is compatible with all of the installed browsers.