Availability of source code and licensing

Is the source code available for review, reuse, or not at all.

We found the following implementation choices:

Source available
An App is implemented as source available if the source code of all of its parts can be examined, but it does not use an open-source license.
Open Source
An app is implemented as open source if all of its parts use an open-source license.
Mixed Source
An app is that uses more than one licensing style, such as open-source and closed-source.
Closed Source
An app is implemented as closed source if none of its parts are available in source code.