Comment # 5 on bug 1200076 from Manfred Hollstein

I was wrongly assuming that the core file should be in my home directory, but
as it was /usr/bin/X which dumped core, the file was in /, of course.

# file /core 
/core: ELF 64-bit LSB core file x86-64, version 1 (SYSV), SVR4-style, from
'/usr/bin/X :0 -seat seat0 -auth /run/lightdm/root/:0 -nolisten tcp vt7
-novtswi', real uid: 0, effective uid: 0, real gid: 0, effective gid: 0,
execfn: '/usr/bin/X', platform: 'x86_64'

I'll attach the compressed core.xz in a minute!