/usr/share/zsh/4.3.11/functions
Edit: /usr/share/zsh/4.3.11/functions/_time_zone (222B)
#compdef -value-,TZ,-default-
local expl
if (( ! $+_zoneinfo_dirs )); then
_zoneinfo_dirs=( /usr/{share,lib,share/lib}/{zoneinfo*,locale/TZ}(/) )
fi
_wanted time-zones expl 'time zone' _files -W _zoneinfo_dirs "$@" -