Updated: June, 15 2021.
The free database is composed by 10.896 games, subdivided by first move. The archives are in CBH and PGN format and they are part of the Goi Database.
Mainly the time per game is 5 and 3 minutes.
Source: games online (only top quality ones), tests and private tournaments. The games are played with Stockfish or derived engines, a little part with Lc0.
Openings stats of the database:
1. e4: 2.500 games
1. d4: 2.500 games
1. c4: 2.500 games
1. Nf3: 1.687 games
1. g3: 813 games
1. f4: 896 games