Reportedly found in - a sampling of interesting provenances

What does "reportedly found in" mean when it appears in a provenance text for an artworks or antiquity?

Below are a few sample texts.

(Texts published by museums are indicated by color.)

Tracking Nazi-looted art dealers: Restitutions as data

What can we learn by analyzing the provenances of artworks which have been restituted to the heirs of Jewish art collectors persecuted by the Nazis?

Patterns. Repetition. Familiar faces. 

Those art dealers who just keep "popping up".

In this post we see what we can learn from the provenance published by auctions houses which have been authorized to sell previously looted art AFTER it has been restituted to the families.