Leave empty = all games.
Name matching is case-sensitive and ignores extra spaces.
Suggestions only show names whose last name starts with what you type.
Abbreviations are recognized: “Heyl, T” also finds “Heyl, Thomas”.
Duplicates: ≥ 90 % prefix of moves, and (compatible player names OR same date). Castling 0-0/O-O normalized. Games without moves are dropped.
When merging, values containing “?” are only used if no better value exists.
Large files are processed in chunks (works up to ~1.4 GB).