Fission is Mozilla's implementation of ''Site Isolation'' in Firefox. Site Isolation is a security feature that offers additional protection in case of large classes of security bugs. Site Isolation safely sandboxes web pages and web frames, isolating them from each other, further strengthening Firefox security.
'''The easiest way to enable or disable Fission:'''
# Open Firefox Nightly's preferences: Open the Hamburger menu.
# Select the "Preferences" or "Options" menu item.
# Select the "Nightly Experiments" menu.
# Check or uncheck the "Fission (Site Isolation)" checkbox.
# Restart Firefox Nightly.
= Why? =