As I understood, fork was just meant conceptually, not as a GitHub/GitLab fork. A git branch is a fork in the timeline of a codebase. The point of the article

As I understood, fork was just meant conceptually, not as a GitHub/GitLab fork. A git branch is a fork in the timeline of a codebase. The point of the article is avoiding feature interaction. Try to implement a feature first on top of a smaller feature set first, just so you can learn about the problem domain and the solution space. After that, integrating such a feature on top of a more complete application should be significantly easier.