Greasy Fork is available in English.
Tumblrs GDPR page is a little bit ridiculous. This will automatically switch all ad sharing to off.
Tumblr decided that in the race to implement GDPR, they had to have the worst possible implementation they could get. This script is simply meant to fix this by automatically disabling all options as fast as possible after the consent page has loaded.
Note: It may look like nothing happened. This is normal as Tumblrs consent page is entirely JavaScript, so the code executes and Tumblrs JavaScript updates the DOM without any rendering happening due to JavaScript still being executed. If they picked CSS and didn't do things like this, you'd see it working live for a split second.