Minecraft wiki entry for Overworld, associated text: The classic finite generator used in late 2009.
The version of the terrain generator used prior to Alpha v1.2.0.
The world generator used from Alpha v1.2.0 to Beta 1.7.3.
The world generator used from Java Edition Beta 1.8 to 1.6.4.
The world generator used from release 1.7 to 1.17.1.
The world generator used from Java Edition 1.18.