While Orion supports saving and viewing the webarchive format used by Safari it does not support the MHTML format used by most Chromium based browsers.
I propose support for viewing this format as well as saving .mht MHTML files.
(Chromium's webpage saving dialog)
A similar dialog could be used allowing the choice between which type of format to be used.
This dialog could also be used to choose the plain HTML saving functionality requested in suggestion #886