Duplicate Posts functionality

Hello there,

on a website we are working on it seems that somehow the “Posts” functionality was duplicated.
That means, that in the backend we have an option in the side menu that is called “Service Manuals”, that has the same “pin” sign next to it as “Posts”. It also has the same functionalities “All Posts”, “Add New” and “Tags” – albeit with other names. The single “posts” listed unter “Service Manuals” looks just like regular posts.

Those posts are then used for a searchable archive of service manuals.
It is imbedded into a page with this shortcode [product_table type=”service_manuals”]

Does anyone know how that was done?
I hope it is understandable what I mean!
I’d love to insert a screenshot…

Thanks and best
Lisa