The Debug -> Log files tab is only displayed when logging of debug information into log files is enabled for at least one type of debug. This can be achieved either by adjusting certain settings or by adding certain keys into the appSettings section of your web.config file. Please see the topics about particular debugs above or the General settings and keys for all debugs topic below for more details.
This tab provides an overview of all log files stored in the ~\App_Data\ folder. By clicking the Delete () button, you can delete the respective file from the App_Data folder.