Additional IP Rights Grant (Patents)

"This implementation" means the copyrightable works distributed by
Google as part of the Upspin project.

Google hereby grants to You a perpetual, worldwide, non-exclusive,
no-charge, royalty-free, irrevocable (except as stated in this section)
patent license to make, have made, use, offer to sell, sell, import,
transfer and otherwise run, modify and propagate the contents of this
implementation of Upspin, where such license applies only to those patent
claims, both currently owned or controlled by Google and acquired in
the future, licensable by Google that are necessarily infringed by this
implementation of Upspin.  This grant does not include claims that would be
infringed only as a consequence of further modification of this
implementation.  If you or your agent or exclusive licensee institute or
order or agree to the institution of patent litigation against any
entity (including a cross-claim or counterclaim in a lawsuit) alleging
that this implementation of Upspin or any code incorporated within this
implementation of Upspin constitutes direct or contributory patent
infringement, or inducement of patent infringement, then any patent
rights granted to you under this License for this implementation of Upspin
shall terminate as of the date such litigation is filed.