Try 2: Add get and post/pages abilities.

src/wp-includes/abilities.php

@@ -9,6 +9,7 @@
 
 declare( strict_types = 1 );
 
+require_once __DIR__ . '/abilities/class-wp-post-type-abilities.php';
 /**
  * Registers the core ability categories.
  *
@@ -30,6 +31,14 @@ function wp_register_core_ability_categories(): void {
 			'description' => __( 'Abilities that retrieve or modify user information and settings.' ),
 		)
 	);
+
+	wp_register_ability_category(
+		'post',
+		array(
+			'label'       => __( 'Post' ),
+			'description' => __( 'Abilities related to the creation and management of posts of all types.' ),
+		)
+	);
 }
 
 /**
@@ -257,4 +266,5 @@ function wp_register_core_abilities(): void {
 			),
 		)
 	);
+	WP_Post_Type_Abilities::register();
 }