The Date and Day Checker Extension is a Chrome add-on developed by SABE-san. It verifies the accuracy of date and day combinations in selected text, ensuring correctness. Users can customize the default year value to something other than the current year.

To use this extension, simply select the text in your browser that you want to check for dates, then invoke the extension from the context menu (right-click, etc.). Once activated, the extension detects potential date and day combinations within the text, confirms their accuracy, and displays the results. For example, if the text mentions January 1, 2024, as a Tuesday when it's actually a Monday, the extension will alert you to the incorrect combination.