Fri Dec 19 19:26:27 UTC 1986
While I agree that setting TZ in the environment is best used
for a user modification of the default, you have to admit that
an implementation that read /etc/timezone every time you did
an ls -l or called ctime for logging would be awfully slow.
This is why I liked the ftime system call notion; it's impossible
to forge, easy to default, easy to configure, and fast.
More information about the tz