MB Admin Columns - Add Custom Non-Meta Column

custom.php

<?php
class Prefix_Custom_Admin_Columns extends MB_Admin_Columns_Post {
	public function columns( $columns ) {
		$columns = parent::columns( $columns );

		/**
		 * Add more column in a specific position
		 *
		 * @param string $position New column position. Empty to not specify the position. Could be 'before', 'after' or 'replace'
		 * @param string $target The target column. Used with combination with $position
		 */
		$position = '';
		$target   = '';
		$this->add( $columns, 'column_id', 'Column Title', $position, $target );

		// Add more if you want

		return $columns;
	}

	public function show( $column, $post_id ) {
		switch ( $column ) {
			case 'column_id':
				echo 'Column content';
				break;
			// More columns
		}
	}
}

functions.php

<?php
add_action( 'admin_init', 'prefix_add_custom_columns', 20 );
function prefix_add_custom_columns() {
	require_once 'custom.php';
	new Prefix_Custom_Admin_Columns( 'post', array() );
}