We have various license headers and similar places with the boilerplate telling people to "write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA." if they did not receive a copy of the GPL with the software. As Debian's Lintian tool points out, the FSF has actually moved offices since then and now the recommended boilerplate is just:
You should have received a copy of the GNU General Public License along with this program. If not, see <https://www.gnu.org/licenses/>.