Waterfox is not available for Ubuntu(Linux). To install Waterfox on Ubuntu machine you need Wine package installed.
Wine
Wine is a compatibility layer which allows Windows applications to run
on Linux by translating Windows system calls into native Linux calls.
Download the Waterfox installer from here and install it using Wine.
or the alternate way is to install Firefox 64 bit. http://www.firefox64bit.com
Download link for Firefox 64bit OS
Installation steps:
cd /tmp
wget 'http://www.firefox64bit.com/firefox.en-US.linux-x86_64.tar.bz2'
Extract the file to /opt or ~/firefox directory
sudo tar -jxvf firefox.en-US.linux-x86_64.tar.bz2 -C /opt
or
tar -jxvf firefox.en-US.linux-x86_64.tar.bz2 -C ~/firefox
about:buildconfig
,about:support
and looking forx86_64
– Wilf Mar 28 '15 at 17:24