WordPress allows extensions only on posts, but having extensions on pages can be helpful too. So if you’re moving to the WordPress platform, but want to have your pages use extensions like .html, .htm, .jsp, or any other, this is the plugin for you.
Unlike other similar plugins, this one allows you to choose the extension with no pre-determined options. And you can change it anytime. This is particularly handy if you manage multiple sites since you can use the same plugin on all of them.