tr's configuration now has a new option remove-content-if, you can use it to remove cards from build, e.g. you don't want to publish drafts
(define (remove-content-p source-path)
(define segs (map path->string (explode-path source-path)))
(and (equal? "content" (first segs))
(equal? "drafts" (second segs))))
(define site
(hash ...
'remove-content-if remove-content-p))