firefox now shows characters as squares instead of normal letters so
that it is unusable.
I removed all history but it did not change anything.
I created a new profile but it is still the same.
I found one thing that works: untick "allow websites to use their own fonts".
But why?
I have 2 F25 computers, this happens only on one of them (the one on
which I use the nvidia proprietary drivers).
Frédéric