Addendum:
Reading the styleguids for PROM and Scores on Condluence, I am also not sure if there is a general agreement on the labels used for instrument elements. In the PROM styleguide there is a sentance about using a “short text representing the content of the question” and in the Score styleguide it says “elements should be named as the exact text of the question in the source material”. This confuses me more and some insights would be much appreciated.