I had always read this as a metaphorical memo. Not necessarily that every team must have a software service running somewhere in infrastructure serving RESTful

I had always read this as a metaphorical memo. Not necessarily that every team must have a software service running somewhere in infrastructure serving RESTful routes but rather as a way of thinking about agreements between groups. Your team's "API" could be documents describing: if you want us to do XYZ, send us a request via ABC, and you should expect a response in UVW format in x amount of time.