Firefox: How do we save a web page as one single file?

+ Browse to https://addons.mozilla.org/en-US/firefox/addon/mozilla-archive-format/.

+ Click on “Add to Firefox” button to install the add-on. 

+ Restart the browser.

+ Visit any web page.

+ Click on Menu > File > Save Page As. 

+ Give a file name. 

+ Save as type: Web Archive, MAFF (*.maff).

+ Click on Save button.
+ Menu > Tools > Add-ons > Mozilla Archive Format > Options.
+ Select Interface tab.
+ Untick the checkbox beside the "Tab bar context menu".
+ Press OK button.

+ Done for now.

Wish List:
Make maff file type as part of the Firefox's installation.