GitHub S&M Blocker is a Chrome add-on developed by Santiago Toscanini. It falls under the category of Browsers and specifically the subcategory of Add-ons & Tools. This free add-on aims to help users avoid Squash & Merge PRs when merging to defined branches on GitHub.

The main feature of GitHub S&M Blocker is its ability to block the "Squash & Merge" option on GitHub pull requests. By defining a set of branches using regular expressions, users can prevent the "Squash and Merge" option from appearing when viewing open pull requests for those branches. This can be useful for teams or individuals who prefer to use other merging options and want to ensure consistency in their development workflow.

With GitHub S&M Blocker, users can have more control over their merging process on GitHub and avoid accidental use of the "Squash & Merge" option. It provides a simple and effective solution for those who want to enforce certain merging practices in their GitHub repositories.