You're focussing on the wrong string. In what is not a constituent; it just happens to occur here. It breaks down into [in [what some are seeing as [a failure [to VP]]]], which means the same thing as in a failure to VP. The what is the marker for a headless relative (aka embedded question complement), which is a noun clause and therefore the object of the preposition in. Look for the ...
relative clauses - Can anyone explain the use of "in what" in the ...
Our numbers have a specific two-letter combination that tells us how the number sounds. For example 9th 3rd 301st What do we call these special sounds?
What do we call the “rd” in “3ʳᵈ” and the “th” in “9ᵗʰ”?
Better is to choose between PUT and POST based on idempotence of the action. PUT implies putting a resource - completely replacing whatever is available at the given URL with a different thing. By definition, a PUT is idempotent. Do it as many times as you like, and the result is the same. x=5 is idempotent. You can PUT a resource whether it previously exists, or not (eg, to Create, or to ...
What does the @ symbol do in Python? What's the syntactic or practical benefit of having decorators here, instead of (for example) just calling something like app.route("/", hello) immediately after defining hello, or even defining hello as a lambda in the arguments to app.route? (The latter example is common with Node.js http.Server and Express routes.)
What does the "at" (@) symbol do in Python? - Stack Overflow