Source

File: wp-admin/includes/schema.php

function populate_roles_210() {
	$roles = array( 'administrator', 'editor' );
	foreach ( $roles as $role ) {
		$role = get_role( $role );
		if ( empty( $role ) ) {
			continue;
		}

		$role->add_cap( 'edit_others_pages' );
		$role->add_cap( 'edit_published_pages' );
		$role->add_cap( 'publish_pages' );
		$role->add_cap( 'delete_pages' );
		$role->add_cap( 'delete_others_pages' );
		$role->add_cap( 'delete_published_pages' );
		$role->add_cap( 'delete_posts' );
		$role->add_cap( 'delete_others_posts' );
		$role->add_cap( 'delete_published_posts' );
		$role->add_cap( 'delete_private_posts' );
		$role->add_cap( 'edit_private_posts' );
		$role->add_cap( 'read_private_posts' );
		$role->add_cap( 'delete_private_pages' );
		$role->add_cap( 'edit_private_pages' );
		$role->add_cap( 'read_private_pages' );
	}

	$role = get_role( 'administrator' );
	if ( ! empty( $role ) ) {
		$role->add_cap( 'delete_users' );
		$role->add_cap( 'create_users' );
	}

	$role = get_role( 'author' );
	if ( ! empty( $role ) ) {
		$role->add_cap( 'delete_posts' );
		$role->add_cap( 'delete_published_posts' );
	}

	$role = get_role( 'contributor' );
	if ( ! empty( $role ) ) {
		$role->add_cap( 'delete_posts' );
	}
}