Based on this wikipedia paragraph, what original tool was Kubernetes based on?

Kubernetes (κυβερνήτης kubernḗtēs, Greek for "steersman, navigator" or "guide", and the etymological root of cybernetics)[4] was announced by Google in mid-2014.[7] The project was created by Joe Beda, Brendan Burns, and Craig McLuckie,[8][9] who were soon joined by other Google engineers, including Brian Grant and Tim Hockin.[7]

The design and development of Kubernetes was influenced by Google's Borg cluster manager. Many of its top contributors had previously worked on Borg;[10][11] they codenamed Kubernetes "Project 7" after the Star Trek ex-Borg character Seven of Nine[12] and gave its logo a seven-spoked wheel. Unlike Borg, which was written in C++,[10] Kubernetes source code is in the Go language.

Kubernetes 1.0 was released on July 21, 2015.[13] Google worked with the Linux Foundation to form the Cloud Native Computing Foundation (CNCF)[14] and offered Kubernetes as a seed technology. In February 2016,[15] the Helm[16][17] package manager for Kubernetes was released.

Kubernetes was originally based on Google's Borg cluster manager tool.