The code repository stores the libraries and helps manage the dependencies of the different libraries. Ages ago, when Java projects used ANT as a build tool and without the later-added Ivy dependency management, the libraries that were needed by a project were downloaded to the source code, usually to the lib library. If a library needed another library, those were also downloaded and stored manually, and this continued until all the libraries that one of the already downloaded libraries needed were copied to the source code tree.
This was a lot of manual work and, also, the library code was stored in the source code repository as many copies. A compiled library is not a source code and has nothing to do in the source ...
