Many large companies push this stuff out for publicity and recruitment. Sometimes employees are encouraged to spend a little bit of their time on it or to brand extracurricular activities with the company name for publicity.

The test for open source is if it keeps getting maintained and supported for years. That only happens when the project is a core business effort, has some direct means of support (e.g. dual licensing or SaaS), or happens to be one of the few genuinely volunteer driven large scale open source projects.