List,

As a followup, here is a close-to-minimal example which demonstrates the failure when \placebtxrendering is omitted.

When run as given, the extract field content is not displayed. When the commented line is uncommented, the result includes the content.

\startbuffer[quotedatabase]
@quote{qSchopA02,
  extract = {Es wäre gut Bücher kaufen, wenn man die Zeit, sie zu
             lesen, mitkaufen könnte, aber man verweschelt meistens
             den Ankauf der Bücher mit dem Aneignen ihres Inhalts.},
  author  = {Schopenhauer, Arthur},
}
\stopbuffer
\usebtxdataset
  [quotedb]
  [quotedatabase.buffer]
\definebtxrendering
  [quotedb]
  [dataset=quotedb]
\setupbtx
  [dataset=quotedb]

\starttext

  Extract:\par
  \cite[extract][qSchopA02]

  Rendering:\par
%  \placebtxrendering [quotedb][method=dataset]

  Completeness:\par
  \showbtxdatasetcompleteness[dataset=quotedb]
\stoptext

The log does not indicate any issues.

Is this expected? Is \placebtxrendering required?

--
Rik