In recent months, the Netherlands has been particularly careful when it comes to testing air travelers. Those who switched had to submit a negative PCR result as well. A same-day antigen test was also required when entering the country.
There is now a relief for transfer passengers: If the transit zone of Amsterdam Airport Schiphol is not left, there is no obligation to present the negative PCR result. This means that those who change can use the airport without a test. In practice, this is likely to be of minor importance, since most target countries require negative results to be submitted anyway.
For those who have been vaccinated, however, it is an advantage, because if the destination allows entry without a PCR test, there is no longer a need to do a test to switch to Schiphol. At the moment there are still very many countries that insist on a negative test, mostly PCR, regardless of the vaccination.