rkh/Smallest-Federated-Wiki — comment on commit 897d46c0dd563b9aa9b3c0961935db184891e376
File:  line 0
By GerryG:

This is the "rackup" configuration for the application. You can add middlewares to your application here.

I don't think this would change the way it functions, even for MS platforms. The "map '/' do" is just saying to route / and everything under it to Controller (as a Rack app), and that should match all paths. The other form just skips the match to everything, but I support some pathology is possible.