alt Hacker Newsyup, I think there are few public articles on aws mantle so you can look it up, but internally this is pretty common knowledge. The entire inference engine of bedrock is built and maintained by a handful of ec2 engineers (all principals and above). Judging by the commit history of the project they are able to just build independent of any of the traditional bureaucracy.
the way in which Mantle was built is highlighted internally by PEs as some sort of triumph but really its a fairly tone deaf indicted of AWS’s engineering culture ... “To achieve a meaningful result in a reasonable amount of time we had to break nearly ever constraint that we force all other engineers to work under. good luck to you plebs of L6 and below”