Project owners are realizing the benefits of teamwork, leading to increased recognition of collaboration among developers in software engineering. A good understanding of how developers work together could positively impact software development practices. To investigate the collaboration habits of developers in project files we leverage the World of Code (WoC) dataset and GitHub API, in this paper. We first identify the collaborations levels of developers in the project files, such as the source, test, documentation, and build files, using the Author Cross Entropy (ACE). We find out that test files report the highest degree of collaboration among the developers, perhaps because collaboration is critical to ensure the convergence of functionality tests. Furthermore, the source code files show the least degree of collaboration, perhaps because of code ownership and the complexity and difficulty in code modification. Secondly, given the widespread usage of the Python programming language, we investigate the Python code tokens that are more prone to change and require collaboration. Our findings offer insights into the specific project files and Python code tokens that developers typically collaborate on in the open-source community. This information can be used by researchers and developers to enhance existing collaboration platforms and tools.