Hans van der Meer schrieb am 26.04.2019 um 12:21:

This does not what I have in mind:

\setupheadertexts[text][chapter][\pagenumber chapter][pagenumber][chapter]

Instead of [\pagenumber chapter] I thought [\pagenumber \chapter] would give me in the header both the pagenumber and the recorded chapter title.

However \chapter turns out to be undefined, neither did \chaptertitle. What is the macro to be called?

I doubt \chapter is undefined otherwise you can add a chapter title to your document.

What you're looking for is the \getmarking marking which is used to access section
titles and number in the header and footer lines, e.g.

\setupheadertexts
[chapter] [pagenumber]
[\prefixedpagenumber] [{\getmarking[chapter]}]

Wolfgang