Post type, field and taxonomy slug prefix
Easy Post Types and Fields displays a friendly version of the slug in the WordPress admin, which can be used when displaying the data using the Posts Table Pro plugin. This article explains how the plugin adds a prefix before the slug of your post types and fields.
Custom post types created with Easy Post Types
When you display post types in Posts Table Pro, you can use the friendly slug which is displayed on the Easy Post Types and Fields settings pages. However, developers should note that the plugin adds a prefix of ept_ behind the scenes. For example, if the friendly slug is article then it is actually ept_article.
For custom taxonomies and fields, the slug prefix also includes the post-type slug. For example, if you create a section taxonomy and a reference field for your article post type, then the slugs would be ept_article_section and ept_article_reference, respectively.
This is done in order to avoid any clashes with other factory or custom taxonomies and fields and you need to know this if you are retrieving the custom post type, custom field or custom taxonomy programmatically.
Adding custom fields and taxonomies to existing post types
The post-type-slug prefix is also added when you add a custom taxonomy or field to native WordPress or third-party post types.
For example, if you add a section taxonomy and reference field to the WordPress factory post type, then their slugs would be post_section and post_reference, respectively. Another example: if you add a brand taxonomy and a brand-sku field to the WooCommerce product post type, their slugs will be product_brand and product_brand-sku, respectively.