A group of Israeli researchers explored the security of the Visual Studio Code marketplace and managed to "infect" over 100 organizations by trojanizing a copy of the popular 'Dracula Official theme to include risky code. Further research into the VSCode Marketplace found thousands of extensions with millions of installs.
Ah it makes more sense that way, I didn’t read the title as if they were talking about all the extensions that they found summed together. This does make it really clear that you should always check extensions when installing them, and not just install extensions with a low install base from an unknown author.