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.)

DATASET: Montreal Museum of Fine Arts Provenance Research Project

The Montreal Museum of Fine Arts maintains an "up-to-date register of all works with incomplete provenance records for the years 1933 to 1945" in order to facilitate provenance research.

We have put the information into an easy to use file for digital analysis.

VIEW MBAM artworks with incomplete provenances 1933-1945 HERE.

DOWNLOAD CSV HERE.

Artworks whose provenance records are incomplete for the years 1933 to 1945.

RKD Provenances that mention the Dallas Museum of Art

It is difficult to find the provenance of European artwork on the website of the Dallas Museum of Art (DMA). However by searching the excellent RKD site, one can find the ownership history of at least a few artworks connected in some way to the city of Dallas. 

One notes the frequent mention (in 24 artworks) of the art dealer Sidney Janis.

These provenances are presented below in an easy-to-download CSV file for art historians.  

Provenances of some artworks in the Dallas Museum of Art collection published on RKD

File format: CSV

Download CSV 

Google Sheet: https://docs.google.com/spreadsheets/d/e/2PACX-1vTCn6yk6PDqgWFxN7HWJ77n8pP5PTPd1NatmaD1c2LQGVcZ5oDgD5gOoMy-BIO50a-SRnTFqvYQOIvu/pubhtml?gid=1529212008&single=true