We'll create fresh WordPress site with MU Plugins Tool installed. You have 20 minutes to test the plugin after that site we'll be deleted.
When you activate MU Plugins Tool, a folder named ‘mu-plugins’ is created, if necessary, in your WordPress installation (default ‘WordPress_Root/wp-content/mu-plugins’) and a starter mu-plugin is created. The starter mu-plugin changes the admin footer text once you’ve enabled it through MU Plugins Tool. For more information, see the Codex Must-Use Plugins page.
I would like to thank David Gwyer, the developer of Plugin Options Starter Kit (POSK). It’s an awesome tool for learning the ins and outs of designing an options page for your plugin. MU Plugins Tool would’ve been much harder to make without POSK as a learning tool.