I don't have any clue where to search but if it can help I paste you below the logs from console (when I execute the piece of code mentionned above) because it is different from what is written into uwofl.log output file.
/opt/click.ubuntu.com/uwolf.chromiumos-guy/0.10.30/bin/browser/defaults/preferences/custom-prefs.js:99: prefs parse error: unexpected character
[Parent 7025, Main Thread] WARNING: libmaliit-glib.so.0: cannot open shared object file: No such file or directory: 'glib warning', file /root/.local/share/bsys6/work/librewolf-141.0-1/toolkit/xre/nsSigHandlers.cpp:201
(librewolf:7025): Gtk-WARNING **: 11:50:55.615: libmaliit-glib.so.0: cannot open shared object file: No such file or directory
[Parent 7025, Main Thread] WARNING: Loading IM context type 'Maliit' failed: 'glib warning', file /root/.local/share/bsys6/work/librewolf-141.0-1/toolkit/xre/nsSigHandlers.cpp:201
(librewolf:7025): Gtk-WARNING **: 11:50:55.615: Loading IM context type 'Maliit' failed
[Parent 7025, Main Thread] WARNING: libmaliit-glib.so.0: cannot open shared object file: No such file or directory: 'glib warning', file /root/.local/share/bsys6/work/librewolf-141.0-1/toolkit/xre/nsSigHandlers.cpp:201
(librewolf:7025): Gtk-WARNING **: 11:50:55.733: libmaliit-glib.so.0: cannot open shared object file: No such file or directory
[Parent 7025, Main Thread] WARNING: Loading IM context type 'Maliit' failed: 'glib warning', file /root/.local/share/bsys6/work/librewolf-141.0-1/toolkit/xre/nsSigHandlers.cpp:201
(librewolf:7025): Gtk-WARNING **: 11:50:55.733: Loading IM context type 'Maliit' failed
[Parent 7025, Main Thread] WARNING: libmaliit-glib.so.0: cannot open shared object file: No such file or directory: 'glib warning', file /root/.local/share/bsys6/work/librewolf-141.0-1/toolkit/xre/nsSigHandlers.cpp:201
(librewolf:7025): Gtk-WARNING **: 11:50:56.124: libmaliit-glib.so.0: cannot open shared object file: No such file or directory
[Parent 7025, Main Thread] WARNING: Loading IM context type 'Maliit' failed: 'glib warning', file /root/.local/share/bsys6/work/librewolf-141.0-1/toolkit/xre/nsSigHandlers.cpp:201
(librewolf:7025): Gtk-WARNING **: 11:50:56.124: Loading IM context type 'Maliit' failed
[Parent 7025, Main Thread] WARNING: libmaliit-glib.so.0: cannot open shared object file: No such file or directory: 'glib warning', file /root/.local/share/bsys6/work/librewolf-141.0-1/toolkit/xre/nsSigHandlers.cpp:201
(librewolf:7025): Gtk-WARNING **: 11:50:56.124: libmaliit-glib.so.0: cannot open shared object file: No such file or directory
[Parent 7025, Main Thread] WARNING: Loading IM context type 'Maliit' failed: 'glib warning', file /root/.local/share/bsys6/work/librewolf-141.0-1/toolkit/xre/nsSigHandlers.cpp:201
(librewolf:7025): Gtk-WARNING **: 11:50:56.124: Loading IM context type 'Maliit' failed
[7025] Sandbox: Couldn't open video device /dev/video
[7025] Sandbox: Couldn't open video device /dev/video1
[7025] Sandbox: Couldn't open video device /dev/video0
[1]+ Stopped ./librewolf.sh >> ~/uwolf.log