September 21, 2021
The IETF Trust originally published the Trust Legal Provisions in 2008 and has updated it four times, most recently as TLP 5.0 published in 2015.
The trustees recently noted a confusing clerical error in the TLP where it describes the license we offer on code components of RFCs and other IETF contributions.
Over the years there have been several variations of the BSD license. The most common are the two-clause and three-clause versions. The license we use is is the three-clause BSD license, which is included in full in the TLP. That license is generally known as the Revised or Modified BSD license, while the two-clause license is known as the Simplified license. For reasons lost to history, the TLP 5.0 refers to its license as the Simplified license, even though it is really the Revised license. This name error has been copied into boilerplate in RFCs and I-Ds even though the license itself is correct.