Solved firefox upgrade today fixed by libmap.conf

[jb_fvwm2]

Firefox all of a sudden after a huge pkg upgrade today, would not start
not finding
libvpx.so.11, so a simple edit of
/etc/libmap.conf worked:

[/usr/local/lib/firefox/libxul.so]
libvpx.so.11 /usr/local/lib/libvpx.so.12.0.0

ymmv. 14-2 amd64

[ falkon on the hardware here is unworkably slow still after the "upgrade'
from early last year... fwiw ]