"Open-source software is non-proprietary software that allows anyone to modify, enhance, or simply view the source code behind it. It can enable programmers to work or collaborate on projects created by different teams, companies, and organizations.
Open-source software authors do not view their creations as proprietary and instead release their software under licenses that grant users with the desire and know-how to view, copy, learn, alter, and share its code."
The following companies have notably made some or all of their code Open Source:
