GitHub uses a single, shared counter for issues, pull requests, and discussions within a repository. This means that when you create a new item (be it an issue, pull request, or discussion) in a fresh repository, the numbering starts at 1 and increments for each subsequent item, regardless of its type. Therefore, the numbering sequence is unified across these three categories of items within a repository.

This design simplifies the process of numbering and referencing items within a repository. It provides a consistent and straightforward way to identify and link to specific items using a common numbering system.

While this behavior is consistent and well-documented, it's not explicitly explained in the GitHub documentation because it's a fundamental part of how GitHub organizes and tracks items within repositories. The shared numbering system is a part of GitHub's design for providing a unified issue-tracking system that includes issues, pull requests, and discussions