Favoring jobs is useful to get a better overview about the jobs you like or want to keep an eye on. The job itself won't be reserved.
As you can favor jobs without creating an account first, your favorites will be saved in your browser. You can see your favorite jobs when using the same browser.
You haven't marked a job listing as a favorite yet. Choose a job category, open the job description, and mark it as favorite. After that, return to this page to see a list of your favorites.