I’m not sure where to start with an explanation so I will start with the code that you posted. This is a post for an acf field. This is a URL type of field. ACF stores the field definition as a serialized array in the post_content field.
The post type of this post is probably “acf-field”
This field will be displayed in a field group or as a sub field in some type or repeater stucture. This is determined by the post_parent in the database. This will be the ID of either another “acf-field” post or an “acf-field-group” post.
Beyond this, ACF stores the values of the fields on each post in the _postmeta table.
