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Microsoft published a guide on how to install Linux.
(programming.dev)
From Wikipedia, the free encyclopedia
Linux is a family of open source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds. Linux is typically packaged in a Linux distribution (or distro for short).
Distributions include the Linux kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name GNU/Linux to emphasize the importance of GNU software, causing some controversy.
Community icon by Alpár-Etele Méder, licensed under CC BY 3.0
I’m a bit confused here.
I used to work for a company that published the source code for one of their products. I.e. made it publicly available.
But many of the build tools and build infrastructure were proprietary and internal (not published publicly.)
So I’d say that was open source but not free, since you can’t really build and run it.
Publishing source code is not sufficient to make something "Open Source." Your company's thing was better described as "proprietary with source code available."