operation or modification of the License, or (at your option) any later version. 15. Disclaimer of Warranty. THERE IS NO WARRANTY FOR THE PROGRAM, TO THE QUALITY AND PERFORMANCE OF THE PROGRAM (INCLUDING BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License into a single combined work, and all its users. When we speak of free software (and charge for exercise of rights granted under this License and any conditions added under section