Be careful of what you buy online because....

[Nooone]

See the following stories....
US authorities seize Judaica from Brooklyn auction house in probe of Holocaust loot - Jewish Telegraphic Agency (jta.org)
https://www.israelnationalnews.com/News/...spx/310759
https://www.israelnationalnews.com/News/...spx/311584
https://www.ynetnews.com/article/r1o300towf
https://www.israelnationalnews.com/News/...spx/315555

[Alan_Boskov]

...The ledger disappeared during the Holocaust and therefore is “stolen property,” the letter said...

It depends on how one views it. If there were no survivors present at where the ledger was found, then one could consider the ledger to have been rescued. Of course, putting it up for auction without attempting to locate related to the ledger persons is a moral issue.

[RabbiO]

See the following story....
US authorities seize Judaica from Brooklyn auction house in probe of Holocaust loot - Jewish Telegraphic Agency (jta.org)

And this has to do with buying online how?

[Nooone]

https://www.israelnationalnews.com/News/...spx/313149

[Alan_Boskov]

The following quote I find most frightening from that article:

...several similar items on auction had been removed for reasons of provenance, and even seized by the police.

“This has had the tragic but unintended consequence of distancing heritage documents from public ownership and protection. Items that are at risk of seizure by law enforcement agencies will remain hidden...

Isn't it long overdue for amending any international treaty concerning these issues?

[Nooone]

a good question of International treaties regarding stolen     artifacts......but to work it needs the full cooperation of all nations......in regard to stolen art...there are 2 obstructions:
1] Professioanal organizations of thiefs who take them
2] Unscrupilious collectors who buy them,,,,,,

[Alan_Boskov]

Of course, dealing with stolen art is big money. Heritage documents aren't something that a buyer would have laying on the nearest to the door piece of furniture of which is set up for impressing dinner guests. Therefore, I doubt that these artifacts would command as high an interest as would even postage stamps with Hitler's bust printed onto them, for example.
The main difference in getting cooperation for universal heritage-protection regarding these types of artifacts and getting likewise for stolen art is that stolen art started out being a Jewish problem, despite the fact that the market has branched out into demand for post-War art to be included. This sort of criminal activity which has become the spotlight beginning with Jewish art will certainly enjoy indifference from nations of which choose to connect this form of criminality with Zionist politics, whereas the theft of heritage documents affects every society that uses a written language and is advanced enough to archive such material.

[LAsttime]

80 years after the Shoah of 1933-1946.....still echoes of the present....
Heirs of Holocaust victim sue museum over medieval hagaddah | Israel National News - Arutz Sheva

[Alan_Boskov]

...“The fact that Elisabeth believed, as do the heirs today, in allowing the public to access to the Haggadah, does not give the museum any basis to claim ownership to the family property, then, or today.”...

We're not dealing with some rare Buffalo Nickel, here. Artifacts of such importance should be kept for public view, regardless of who owns them. If this Hagaddah now changes ownership, it doesen't matter one bit, as long as it's kept on display.
The Knesset should be debating on legislating-in a ruling on behalf of such issues.