* page information including:
* 1. The page type. If the plugin page is registered as a submenu page, such as for
* Settings, the page type would be 'settings'. Otherwise the type is 'toplevel'.
* 2. A separator of '_page_'.
* 3. The plugin basename minus the file extension.
*
* page information including:
* 1. The page type. If the plugin page is registered as a submenu page, such as for
* Settings, the page type would be 'settings'. Otherwise the type is 'toplevel'.
* 2. A separator of '_page_'.
* 3. The plugin basename minus the file extension.
*