Reddit User Explorer is a lightweight web extension for accessing past posts and comments of users on Reddit. It is a simple, yet useful tool that will let you browse through the history of posts and comments by a selected user. 

Once you install the extension, you can start using it by selecting the username of a user, just by pressing Ctrl + Left Click. It will fetch all available past posts and comments and then display them on a new tab in your browser. 

This tool can be useful for anyone who needs to browse through the history of posts and comments of a user. It is easy to use and requires no additional permissions.