WP Peon is specifically design for back end developer so that they can easily look, modify WordPress files you can say alternate WP Editor. Goal is to provide friendly access to most common WordPress action and filters.
Custom HTML
Add custom HTML in header, footer and blog posts.
Execute PHP
Help to run PHP code in WordPress posts and pages using shortcodes generated by Execute PHP. Usage Type in shortcode and type in PHP Code and then click save. To create new code just change the shortcode and add renew code below or refresh page to clear existing values.
WP Explorer
An alternate WordPress Source Editor. With directory list view and open folder and nice breadcrumbs.
Advance
Modify .htaccess file or wp-config.php from Advance page. You can also enable debugging with given step and view debug.log directly on page.