The copyright holder for code (or other IP) can choose to apply one or more licenses to their work. That is, the person (or perhaps their employer, depending on their employment agreement) who actually wrote the code owns the copyright, and they can choose to provide it to you under a specific license. They can also provide it to someone else under a different license, or not license it to someone else.
The "community" does not directly matter. However in an open source project, where many different people are writing software together, it depends on the license and the project. Some projects require copyright assignment to the Foundation that runs the project; then the Foundation can choose which licenses it provides. Otherwise, every individual contributor owns their own copyright, and typically the software as a whole is provided to everyone under the same open source license.
To get more detailed than that you need to provide a specific example of the code, licenses, and rights you're asking about.
Note that software on github that does not have a LICENSE file is not licensed to you, only provided under the GitHub terms of service, which only allows you to "to allow others to view and fork your repositories", not otherwise redistribute them at all.