Safari Web Archive
Apple Safari is a web browser which can be used on computers as well as mobile devices such a the iPhone or iPad.
The safari browser is based on the WebKit browser which is open source and used in various mobile telephone operating systems as well as in other browser such as Googles Chrome.
If you save web pages to your computer with safari then the saved pages will have the extension .webarchive.
How to open .webarchive files?
Software to open .webarchive files
What are .webarchive files