ECO E28: Nimzo-Indian Defense

ECO E28 is part of volume E — Indian Defenses. The Lichess chess-openings dataset files one named line under it. It is Nimzo-Indian Defense: Sämisch Variation: 1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. e3 O-O 5. a3 Bxc3+ 6. bxc3.

That position has come up in 66,840 Lichess games between players rated 1600 to 2500: White won 48.7%, 5.1% were drawn and Black won 46.2%.