Hammerklavier op.29 - Rszewski recording off topic??

[Otto Ede Pool]

To my surprise I discovered that the Rszewski recording added to the Beethoven sonata nr 29 (Hammerklavier) page contains a quite elaborate addition to the score:

In the recording of part 4 (the Fugue) a very elaborate "cadenza" - 5 minutes or so- is added just before the final 20 bars. Most probably the source of this cadenza is Rzewski in person.
To be cleat: there is no indication of a cadenza in any of the scores of the Hammerklavier Sonata whatsoever.

My question is how to deal with this.
The recording of the Sonata is of substantial quality, however an addition like this does not seem to be in the spirit of the imslp project (and not in Beethovens spirit for that matter, Beethoven is known to have admonished performers of his works with especially this behaviour....).

Two possible solutions:
- a substantial "liberty" or "addition" should be noted clearly in a comment on the uploaded recording. However a place for a redactional comment on an uploaded recording seems to be missing (i wonder why...).
- remove this recording for not representing the Hammerklavier fugue score, and guide mr Rszewski to his own imslp or wikipedia page, or youtube channel for this recording.

Opinions please..

[Eric]

Frederic Rzewski is very well-known for improvisation, in his own music as well (and for encouraging it there). I'd be more concerned if this were the only existing recording of the work, but this is hardly the case!