As part of the new experiment, Google is introducing "before" and "after" commands that can be used individually, or combined, to bring custom dates to the search box. To borrow Google's example, typing "avengers endgame after:2019-04-01" will return results for the movie after that date. The same applies to "avengers endgame before:2019-04-01." Or you could combine the two commands to search between a set time period, for example: "avengers endgame after:2019-03-01 before:2019-03-05."
It's a power move for power users, made even faster if you just enter a year, which Google automatically translates into full dates at the beginning or end of the year. Search can also recognize dates with either dashes or slashes.
Google adds that it's nixing the "sort-by-date" option, except for news search due to lack of use. It may also hide the publication dates of search result pages, though this is still under consideration and won't be applied to the news tab. Blaming a lack of a standard for dates on the web, Google says that by relying on guesswork it risks publishing inaccurate dates. The new features are available in beta now and will roll out widely soon.