The eval code in the plugin code

Hi there,
I’m just curious;

Why do you need the ‘?>’ piece in the eval code below?

eval( ‘?>’ . $text ); // which is in your plugin code

I understand that it won’t work without it and that you do need it, but could not figure out what is it that’s doing.

https://www.ads-software.com/plugins/enable-shortcode-and-php-support-in-text-widget/