Hide and Seek is a free Chrome add-on developed by roush.kyle. It falls under the category of Browsers and specifically the subcategory of Add-ons & Tools. This handy tool is designed to make working with pull requests on GitHub easier and more efficient.

Hide and Seek allows users to "complete" files in a pull request, providing a convenient way to hide files that have been reviewed or are no longer relevant. When a file is completed, it is automatically hidden from view. Even when revisiting the page, the add-on remembers the completed files and keeps them hidden, saving valuable time and effort.

However, if there are any changes made to a completed file, Hide and Seek will automatically "uncomplete" the file and add a thinking emoji, indicating that further review is required. This feature ensures that completed files are not overlooked in case any modifications are made.

Additionally, Hide and Seek provides a progress bar that displays the completion percentage of other diffstats. This allows users to easily track their progress and share their completion percentage with others when submitting a review to a pull request.

Overall, Hide and Seek is a useful tool for GitHub users who frequently work with pull requests. Its ability to remember completed files and provide a progress bar adds convenience and efficiency to the review process.