(such as an express permission to practice a patent or covenant not to

sue for patent infringement)''.

``Express'', as used GPLv3~\S11\P3, is a term often used in legal writing as

an antonym to ``implied''.  Thus, GPLv3's definition of ``patent license''

does not include those patent licenses which arise by

Instead, GPLv3~\S11\P3--5 are specifically concerned with explicit promises

that are purportedly legally enforceable.

Nevertheless, unlike traditional commercial patent licensing

agreements\footnote{Typically, well-drafted commercial patent license

  agreements explicitly exclude any possibility of