Github: https://github.com/saenzramiro/rambox
"Portable" downloads (x32 & x64): https://github.com/saenzramiro/rambox/releases
Authors wrote:Free and Open Source messaging and emailing app that combines common web applications into one.
Tested: Not Portable
\AppData\Roaming\Rambox (main settings)
\AppData\Local\Temp (Icon files)
However, settings can be synced online (and thus between computers) by creating/logging in with a Rambox or Google account.