What is the purpose of X-Mx-ReqToken header?

Question

What is the use of X-Mx-ReqToken HTTP header? Almost all tutorials on enabling CORS in nginx whitelist the X-Mx-ReqToken header. But I can't find any information on the purpose of the header.

Answer 1

X-Mx-ReqToken is a header used to supply a profiler key for Mendix Runtime:

Member Data Documentation

final String com.mendix.systemwideinterfaces.core.IProfiler.PROFILER_KEY = "X-Mx-ReqToken" [static]

Basically, this is just a case of copying & pasting the same snippet over and over again until it made it to every nginx CORS tutorial out there. But unless you actually use said profiler, it's safe to omit.