about:support
Multiprocess Windows
about:config
browser.tabs.remote.autostart | 1
criar - browser.tabs.remote.force-enable | 1
accessibility.force_disabled | 1
http://techdows.com/2016/08/firefox-48-e10s-enabled-or-disabled-if-disa…
como root:
cd /opt
wget https://ftp.mozilla.org/pub/firefox/releases/56.0.2/linux-x86_64/pt-PT/firefox-56.0.2.tar.bz2
tar xjf firefox-56.0.2.tar.bz2
rm firefox-56.0.2.tar.bz2
chown -Rv user:user firefox/
mv /usr/lib/firefox-esr/firefox-esr /usr/lib/firefox-esr/firefox-esr.old
ln -s /opt/firefox/firefox /usr/lib/firefox-esr/firefox-esr
http://libre-software.net/how-to-install-firefox-on-ubuntu-linux-mint/