The USAF is Integrating the GBU-57 Into the B-2

Stephen Trimble, who has a lot more patience than I do, notices a solicitiation document for bids to integrate the GBU-57 into the B-2.

He does some research, and all he can find is a reference to it being a 5000lb penetrating bomb from an article in the Grauniad^* circa 2003, but this appears to be an error actually referring to the GBU-28.

So, why is the USAF putting out bids to integrate a new weapon into the B-2? Why does it appear to be a penetrator?

Is this a preparation for a first strike on Iran?

^*According to the Wiki, The Guardian, formerly the Manchester Guardian in the UK. It's nicknamed the Grauniad because of its penchant for typographical errors, "The nickname The Grauniad for the paper originated with the satirical magazine Private Eye. It came about because of its reputation for frequent and sometimes unintentionally amusing typographical errors, hence the popular myth that the paper once misspelled its own name on the page one masthead as The Gaurdian, though many recall the more inventive The Grauniad."