Their data is based on a survey. According to LinkedIn, the following number of jobs per company have been created in the past week: Google 7k+ Apple 2k+ Amazon 39k+ Meta 2k+ If anyone has that premium feature (I don't have it anymore), you can check how the numbers changed over time.
I don't understand how they could have Google's true job posting numbers. Many of our postings are for general SWE roles, and that posting could hide any number of actual openings.