I have the impression that some of the comments in the Russia section in file 'europe' have not been followed through in the actual zone tables.

I refer to the lines beginning here

# From Stepan Golosunov (2016-03-07):
# 11. Regions-violators, 1981-1982.
# Wikipedia refers to
# http://maps.monetonos.ru/maps/raznoe/Old_Maps/Old_Maps/Articles/022/3_1981.html
# http://besp.narod.ru/nauka_1981_3.htm

... until
# 12. Udmurtia

Also the Russian wikipedia page
https://ru.wikipedia.org/wiki/%D0%9C%D0%BE%D1%81%D0%BA%D0%BE%D0%B2%D1%81%D0%BA%D0%BE%D0%B5_%D0%B2%D1%80%D0%B5%D0%BC%D1%8F#%D0%9F%D0%B5%D1%80%D0%B5%D0%BC%D0%B5%D1%89%D0%B5%D0%BD%D0%B8%D0%B5_%D0%B3%D1%80%D0%B0%D0%BD%D0%B8%D1%86%D1%8B_%D0%BF%D1%80%D0%B8%D0%BC%D0%B5%D0%BD%D0%B5%D0%BD%D0%B8%D1%8F_%D0%BC%D0%BE%D1%81%D0%BA%D0%BE%D0%B2%D1%81%D0%BA%D0%BE%D0%B3%D0%BE_%D0%B2%D1%80%D0%B5%D0%BC%D0%B5%D0%BD%D0%B8_%D0%BD%D0%B0_%D0%B2%D0%BE%D1%81%D1%82%D0%BE%D0%BA

contains the sentence (in Google translation)

In the autumn of 1981, Arkhangelsk, Vologda, Yaroslavl, Ivanovo, Vladimir, Ryazan, Lipetsk, Voronezh, Rostov-on-Don, Krasnodar and regions to the east of those named (about 30 in total) parted ways with Moscow time. However, the convenience of common time with Moscow turned out to be decisive - in 1982, these regions again switched to Moscow time.

Shanks International atlas has similar information, and also the Russian book
Zaitsev A., Kutalev D. A new astrologer's reference book. Coordinates of cities and time corrections, - The World of Urania, 2012
Russian: Зайцев А., Куталёв Д., Новый справочник астролога. Координаты городов и временные поправки

To me it seems that an extra zone is needed, which starts with LMT util 1919, later follows Moscow since 1930, but deviates from it between 1 October 1981 until 1 April 1982.

I suggest to call this zone Europe/Yaroslavl, because Yaroslavl with a population of 608'000 seems to be largest city in the deviating area.