To designate the facility of the United States Postal Service located at 29 Franklin Street in Petersburg, Virginia, as the "John Mercer Langston Post Office Building".

What it does

A plain-language summary is coming. Here is the official summary from the Congressional Research Service:

This act designates the facility of the U.S. Postal Service located at 29 Franklin Street in Petersburg, Virginia, as the John Mercer Langston Post Office Building.