The bill H.R. 6912 directs the Librarian of Congress to acquire and install a stained glass panel featuring the seal of the District of Columbia. This panel is to be placed among existing stained glass panels depicting the seals of U.S. states, which are located overlooking...
Simple Explanation
The bill says that a pretty window with a picture of the coat of arms for Washington, D.C. should be added to the Library of Congress, where other windows show pictures from different states. This is so Washington, D.C., can be shown with all the states.