gnome-shell recently changed its window manager warning messages to
include the titles of windows. This logs potentially sensitive user
information in system log files.
Previous log message format:
Aug 13 10:06:05 o gnome-shell[1072]: Window manager warning: Ping serial 79896884 was reused for window W1, previous use was for window W128.
New log message format:
Dec 13 18:00:59 o gnome-shell[1120]: Window manager warning: Ping serial 35993321 was reused for window W1 (Facing the Git commit-ID collision catastrophe [LWN.net] — Mozilla Firefox), previous use was for window W33 (~).
Many user processes are careful to avoid logging potentially sensitive
information, and this breaks that expectation.
(I recognize that this is a tradeoff between user privacy and the
usefulness of log files.)