[time.zone.db.tzdb]/1:

Each vector in a tzdb object is sorted to enable fast lookup.

The time zone names are sorted in the tzdb produced by MSVC's STL¹, but locate_zone performs a linear search. It could be changed to a binary search, which would be faster.

This is slightly more advanced than a "good first issue", requiring the contributor to understand how to perform binary search using std::lower_bound (not std::binary_search!).