Line Number Markdown is a free Chrome add-on developed by iVapor. This add-on falls under the category of Browsers and specifically the subcategory of Add-ons & Tools. Its main functionality is to display line numbers in Markdown code blocks.

With Line Number Markdown, users can easily add line numbers to their Markdown code blocks, making it easier for others to reference specific lines of code. This can be particularly useful for code reviews, collaborations, and discussions.

To use Line Number Markdown, simply install the add-on on your Chrome browser and refresh the webpage if the line numbers don't appear immediately. Once installed, line numbers will be automatically displayed in Markdown code blocks, enhancing the readability and navigability of your code.

Line Number Markdown is a handy tool for developers, programmers, and anyone working with Markdown code. It simplifies the process of referencing and discussing specific lines of code, improving collaboration and productivity.