Question about From & To rule fields...just t be certain I understand

[Philip Warner]

I'd like to clarify which year should be compared in from/to fields for
rules (and zone lines). It seems reasonable that the AT field determines
which year is to be compared (wallclock, utc or standard) -- is that
correct?

To give specific example:

Rule    Test    1999    only    -    Jan    1     0:00    2:00    -
Rule    Test    2000    only    -    Jan    1     0:00    0:00    -

These are both wallclock rules, and suppose they are used in a region
that is GMT+5. Then at UTC  31-Dec-1999 17:00 the WC time will turn to
midnight....is that the point at which the clocks would be adjusted?

And if so, in the following example:

Rule    Test    1999    only    -    Jan    1     0:00    2:00u    -
Rule    Test    2000    only    -    Jan    1     0:00    0:00u    -

would the clocks adjust at UTC time 1-Jan-2000?