Performance of editor in broadcast about foremost of newspapers (9)
I believe the answer is:
rendition
'performance' is the definition.
(rendition is a kind of performance)
'editor in broadcast about foremost of newspapers' is the wordplay.
'broadcast' indicates an anagram.
'about' is an insertion indicator.
'foremost of' suggests taking the first letters.
The first letter of 'newspapers' is 'n'.
'editor'+'in'='editorin'
'editorin' with letters rearranged gives 'redition'.
'redition' enclosing 'n' is 'RENDITION'.
'of' acts as a link.
(Other definitions for rendition that I've seen before include "version" , "Account" , "Explanation - interpretation" , "covert if extraordinary" , "Interpretation (of e.g. song)" .)