AD devs: before updating the sync version to 10, please make sure
the new timezone code has been ported over. The core change to the
scheduler is in _updateCutoff():
9736e4a970/pylib/anki/schedv2.py (L1357)
with the following supporting Python functions:
9736e4a970/pylib/anki/schedv2.py (L1410)
_timing_today() is calculated in Rust (lines up to 92, the rest are
tests):
9736e4a970/rslib/src/sched/cutoff.rs (L20)
The change went through a few iterations before stabilising, so it's
probably easier to refer to the above code than the patches that got
us to that point.
131d37dca5
