You can't check the history, it's not saved. Focus is a private browser. It's like browsing in private/incognito mode with any regular browser. In this mode, your search history, browsing history, website settings, passwords, and cookies are not saved for privacy reasons. All this data is stored in the browser only during the session. Once you close the browser, the data is permanently deleted. If you need to save your history, consider installing the classic version of Firefox.