"The GBU-57 was designed with Iranian nuclear bunkers in mind. By 2012, concerns emerged that the original MOP lacked the capability to breach Iran’s most heavily fortified sites. As a result, the Pentagon submitted an $82 million funding request to Congress to enhance the bomb’s penetration capabilities."
https://dsm.forecastinternational.com/2025/06/23/with-gbu-57s-u-s-finally-deploys-weapon-designed-specifically-for-irans-hardened-nuclear-sites/