Since I was not able to reproduce the bug on another computer ... I investigate and found the issue:
ldd /lib/x86_64-linux-gnu/libwebkit2gtk-4.1.so.0.16.3 linux-vdso.so.1 (0x00007ffd0affa000) [...] libgbm.so.1 => /lib/x86_64-linux-gnu/libgbm.so.1 (0x00007fb11a120000) libdrm.so.2 => /opt/amdgpu/lib/x86_64-linux-gnu/libdrm.so.2 (0x00007fb11a107000) libstdc++.so.6 => /lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007fb119e00000) [...] A quick modification in the /etc/ld.so.conf.d directory and the bug is gone. Sorry for the noise. -- Jérôme Kieffer