I just discovered a new meta field on the newly created custom post type page. The meta name is slug, and it's under the wp editor field. What's that, and how can I remove it?
on the top right of the page where you edit your post or page you will see two buttons: [Screen options] and [Help]. Click on [screen options]. You will see all kinds of options, unmark the one labeled "Slug" and it will disappear from the post/page edit page.
If you want to know what that was: http://codex.wordpress.org/Glossary#Post_Slug
Hope that helps