Rated 5 out of 5 stars

Solution to zoom everything (was already previously posted):

Instead of using TF&SC (currently for TB 60 and lower), try this:
≡ > Preferences > Preferences > Advanced > General > Config Editor > I accept the risk! > search for "layout.css.devPixelsPerPx", modify value to "1.5" which is equal to 150%.

now close the settings and profit ;-)

This user has a previous review of this add-on.