Microthemer allows you to view the CSS code it generates by clicking the view CSS icon in the left menu. This can sometimes be useful for debugging issues if you know CSS. Or if you want to reuse the code Microthemer generates elsewhere.
Note: Microthemer adds the !important declaration to all CSS styles by default. If you’re up to speed on CSS specificity you may want to disable this behaviour on the preferences page. If so, you will still be able to apply ‘!important’ declarations on a per-style basis by clicking the faint ‘i’ that will appear to the right of all style option fields.
Also note, it’s possible to deactivate or even uninstall Microthemer and still use the CSS customizations. You just need to paste a small piece of code in your theme’s functions.php file. See this forum post for further information.