What I was describing could maybe be conceptualized as multiple applications that serve one larger site. You have the public facing staticly rendered site, built in whichever way, but that ultimately has accessible rendered content on page load and as fast as possible. Then you also have interfaces to the data that is rendered there, which might be completely separate codebases for different purposes.
These could also take place in things like a reporting portal inside a company, where stakeholders need to regularly see static or filterable reports of pre-rendered data, and then you have other internally available apps that different departments can use to manipulate that data in ways that they can easily receive immediate feedback on whether or not it's valid or how it looks etc..
Once you start adding conditions and context to the heuristic, it starts to look a lot like a Design Pattern.