This makes me wonder what we're the arguments against, is there a read about why NBs were opposed?
Edit: Found an answer by Harald Achitz in comments to the post, but that's a lot to read, it seems:
it's not just one paper, but rather a whole book. Thats the problem.
As an entry point, I recommend:
Procedural problems: P4381 (https://wg21.link/P4381)
Technical problems: P4334 (https://wg21.link/P4334)
Both papers reference plenty of other papers, so they provide a good starting point for getting an overview.
This blog series by Mateusz Pusz also provides an excellent overview of the topic:
https://train-it.eu/blog/series/cpp26-contracts/
My personal favorite topics, the problems for binary package management and the growing number of implementation-defined aspects introduced by contracts are actually not covered exhaustively by any of these sources. (imho)
The response to the technical concerns about build systems and package management was essentially: Nothing new here. The situation is already a mess, so we're just adding more mess. Literally!