Yes! If you view the source of your custom build, you'll see on the second line a link to the custom configuration, i.e.:
/* Modernizr 2.7.1 (Custom Build) | MIT & BSD
* Build: http://modernizr.com/download/#-fontface-borderradius-boxshadow-opacity-cssanimations-csstransforms-csstransitions-geolocation-inlinesvg-svg-touch
*/
Copy/paste that link in your browser, and there's your custom config.