This relatively small extension allows you to replace the Firefox homepage and new tab page with a custom URL. To make the experience as seamless as possible, the page is embedded as an iFrame. For this reason, certain websites may not be displayed because their developers prohibit this type of embedding to prevent fraud.
FAQ Where can I set the custom URL?
Navigate to Extensions->Portal->Preferences.
Does the extension accept local files?
Currently local files can not be used, since Firefox prohibits to embed local files in order to protect user's privacy.
