Firefox: firefox dies quietly. How to debug?

[O. Hartmann]

I'm working on a simple NanoNSD based application using a small autologin image
of FreeBSD 12-CURRENT.

The intention is to autologin a user and start via xinit a X11 session with
Firefox. So far. Autologin works, I can start the X11/wmaker session and also
open xterm, xpdf as clients. But I can not start firefox or libreoffice - they
die quietly. 

I do not see anything in the X11 logs nor do I see logs on the console telling
me something irregularyly has happened. I tried to look for some "verbosity"
flags on firefox, but I didn't find anything suitable.

Does someone here know how to make firefox a bit more verbose?

Any help appreciated.

Please CC me, I'm not subscribing this particular list.

Thanks in advance,
Oliver