validity
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... Implementors should treat Proposed Standards as immature
specifications. It is desirable to implement them in order to gain
experience and to validate, test, and clarify the specification.
However, since the content of Proposed Standards may be changed if
problems are found or better solutions are identified, deploying
...
... copyrights, patents, patent applications, or other rights in the
fulfilling of the its obligations under (A), and will take no
position on the validity or scope of any such rights.
(C) Where the IESG ...
...
"The IETF takes no position regarding the validity or scope of
any intellectual property or other rights that might be claimed
to pertain to the implementation or use of the technology ...