As I recall, tzdb's circa-1880 transitions in the former Russian empire are from Shanks. I have not found independent verification of these transitions, and quite possibly they're imaginary. For what it's worth, the guess recorded in tzdb lists a transition from local mean time to timekeeping based on clocks of major cities nearby, and this guess uses KMT to denote "Kiev Mean Time", as noted in the tzdb comment and listed in <https://data.iana.org/time-zones/theory.html#abbreviations>. Of course we'd like a better source than Shanks for this. Common practice in 19th-century Russia was to keep Moscow time in train stations, regardless of local timekeeping practice. So that is another complexity for Kiev. Another point: these guesses are proleptic, as they use the Gregorian calendar and 19-century Russia was firmly in the Julian camp.