Unfortunately the new UI does not allow to search for leaked phone numbers anymore. The old did (e.g. could check for facebook phone number leak, see https://www.troyhunt.com/the-facebook-phone-numbers-are-now-...). The new does not let it pass through the input field.
Edit: it's also statet in the announcement:
> Just one little thing first - we've dropped username and phone number search support from the website
But it's really a bad time to remove this feature since there's a ongoing law suite against facebook in germany (https://www.vzbv.de/pressemitteilungen/facebook-datenleck-be..., hgerman link) that utilized the search there to know if one can participate or not.
Edit: it's also statet in the announcement:
> Just one little thing first - we've dropped username and phone number search support from the website
But it's really a bad time to remove this feature since there's a ongoing law suite against facebook in germany (https://www.vzbv.de/pressemitteilungen/facebook-datenleck-be..., hgerman link) that utilized the search there to know if one can participate or not.