Forwarding a bug report I got in Debian:
https://bugs.debian.org/805347
When the timer is on, I get the following three warnings once a second
printed into the user journal or to ~/.xsession-errors.
pabs@chianamo ~ $ journalctl -f --user
-- Logs begin at Wed 2015-04-15 08:46:04 AWST. --
Nov 17 15:13:59 chianamo gnome-session[2178]: Indicator.prototype._draw@/usr/share/gnome-shell/extensions/timer@olebowle.gmx.com/extension.js:281
Nov 17 15:14:00 chianamo gnome-session[2178]: (gnome-shell:2243): Gjs-WARNING **: JS ERROR: TypeError: light.from_string is not a function
Nov 17 15:14:00 chianamo gnome-session[2178]: arc@/usr/share/gnome-shell/extensions/timer@olebowle.gmx.com/extension.js:262