Running iceweasel generates a segmentation fault on my system. This is
independent of whether iceweasel is run in safe mode or not.

Debugging with strace shows that this is caused by "resource temporarily
unavailable", in
[11073] ###!!! ABORT: Aborting on channel error.: file
/tmp/buildd/iceweasel-31.1.0esr/ipc/glue/MessageChannel.cpp, line 1531

src:iceweasel has been superseded by src:firefox-esr in version
45.0esr-1 in March 2016. Transitional packages to ease upgrades were
provided in the wheezy, jessie, stretch and buster releases. The
transitional packages have been removed finally before the bullseye
release in August 2021.
After regular security support for buster ended in August 2022 and LTS
support ended in June 2024, I'm closing the remaining bug reports now.

Andreas