Why did this journal retract two 1940s papers by Max Planck?

Clicking on the links now reveals blank pages and empty PDFs. "Intellectually, it’s not acceptable.” https://arstechnica.com/science/2026/06/why-did-this-journal-retract-two-1940s-papers-by-max-planck/?utm_brand=arstechnica&utm_social-type=owned&utm_source=mastodon&utm_medium=social