When people dispute Jewish death tolls in WW2 they often refer to ‘Red Cross Documents’. What are these documents and where can I view them that isn’t a biased website just referring to them?

The claim originates from "Did Six Million Really Die?" an antisemitic pamphlet published by a former leader of the far-right British National Front Richard Verrall.

He claims, among other things, that the Swiss newspaper Die Tat published a statistic in 1955 claiming only 300,000 Jews died in WWII concentration camps based on data from the International Tracing Service, an organization founded by the Red Cross in 1943 to trace and document victims of mass murder at the hands of the Nazi government. The idea was not so much estimate the number of victims, but rather to document who was killed and where.

In reality, the figures published by Die Tat were a report of "Germans and German-speaking Jews" who died and was only a tally of the number of records the Tracing Service had found so far. This was not an estimate of the number of Jews who died at the camps in question; it was the number of identifiable death records of German-speakers that the International Tracing Service had located. It is not, and was never meant to be, an estimate of the total number of people killed. It is not even a tally of identifiable victims, since it doesn't count all the victims who did not speak German (i.e. the vast majority).

Additionally, as it turns out, the Nazis did not actually write down the names of every single person who died, especially if they planned to kill the people in question shortly thereafter. The Nazis also attempted to destroy records of those in the camps in an attempt to conceal what they had done in the last days of the war. As a result, many names are not recoverable via concentration camp records.

As a result, any estimate that uses only the documented victims from a report less than a decade after the fact is going to be grossly understating the number of actual victims of the Holocaust. Since then, roughly 4 million Jewish Holocaust victims have been documented by means other than having their names listed official documentation from concentration camps, with 1-2 million still remaining anonymous. In reality, not every victim can be documented and it's unlikely we will ever know the names of every single person of who died in the Holocaust. Many did not have birth certificates, passports, or financial records of any kind, effectively making them historically untraceable as anything other than a statistic.

In short, coming to the conclusion that the report is evidence that only 300,000 Jews were killed requires willful lying about its contents, misrepresenting its purpose, and ignoring all subsequent findings since then. The Red Cross denounced using its statistics in this way in their 1978 bulletin "False Propaganda," in which they stated that they had "never published—or even compiled—statistics of this kind which are being falsely attributed to it," because again these are not death toll estimates.

As for where you can read about it, I can refer you to a book by Deborah Libstadt called "Denying the Holocaust: The Growing Assault on Truth and Memory." But I don't know of any website (and Google doesn't seem to be cooperating) where you can find discussion of this issue specifically. Because, as it turns out, the only people who seem to care about the findings of this report are the people who want to use it to lie about history. This carries very little interest to anyone else, because most people realize what the document is about if they take any amount of effort to read it, and as a result, it only ever comes up in the context of Holocaust denial. I can refer you to this correspondence the Red Cross Head of Documentation and Dissemination wrote in 1979, but it's essentially a restatement of what I just said.