DeWitt clause
The licence term that forbids you from publishing performance tests of the software without the vendor's permission.
It is named after David DeWitt of the University of Wisconsin, whose group published comparative database benchmarks in the early 1980s. Oracle fared badly, and the response was not a faster database but a licence term: no published measurements without approval. The idea spread quickly to the other big database vendors and survives in today's EULAs and cloud terms of service.
Vendors justify it by saying badly configured tests spread misleading numbers. The practical result is that independent comparisons of commercial databases tend to anonymise the products as "System A" and "System B" – which tells you most of what you need to know about how comfortable vendors are with scrutiny.