How to Customize Right Sidebar in Header Menu? And is it allowed?

Can we customize the right side bar menu from Header ?? if yes then how?
I want to add new Option and route to new page from it

I think it is intentionally not configurable. Apps should not alter the overall style of the NC frontend.

What is the use case?

HI Christianlupus

Actually we want to add one more field in the header menu through which we can route to companies sub domain.

One option might be the external sites app. This is a key-ready solution then.

You could hack into things using JS possibly but this is not very clean in my personal experience and might break in the future. You would fight a war against the NC server versions.