This is what we can read at the above mentioned link:
"This year we celebrate the 100th anniversary of the 6th World Champion Mikhail Botvinnik. In honor of World Champion, ChessOK releases a free training course ”Play Like Mikhail Botvinnik” in Peshka interface.Learn to play like the 6th World Champion Mikhail Botvinnik in 350 most interesting and instructive positions from his games!
This course also features 1.069 games played by Botvinnik from 1924 till 1970. The games are deeply annotated by GM Alexander Khalifman, FIDE World Champion’1999 and IM Sergey Soloviev."