Google has made two changes in Google Search Console over the past 24 hours. Most significantly, the index coverage report now uses mobile-first indexing data when available. Meanwhile, Google has issued notices about sunsetting old Google Search Console reports when similar reports exist in the new Google Search Console.
There are a nice number of SEOs and webmasters in the forums claiming they saw huge changes in terms of their rankings in Google starting on November 22nd or so. Since it was Thanksgiving day and traffic is always off on holidays, it needed more time to confirm. But there are many claims of an update, possibly a reversal of the Medic Update for some that were originally hit on August 1st.
Google has decided to show zero search results when they are confident that they can give answers that solve the searcher’s query fully. This is currently limited to many time, calculations & conversions searches — those that ask for answers to math questions, what the time is in specific locations and for measurement unit conversions. Google always provides a link to “show all results,” under their answer, which will lead the user to full search results.