Hello, you can only delete the auto-fill data right now, not on a per website basis unfortunately. To manage your autofill data, type about:preferences#privacy in the URL bar and press enter. If this answered your question mark as solution.

You can use these steps to remove saved items from an autocomplete drop-down list.

1. click the (empty) input field on the web page to open the drop-down list
2. highlight an entry in the drop-down list with cursor Down key
   do not click the mouse or press the Enter key
3. press the Delete key (on Mac: Shift+Delete) to delete the highlighted entry

Note that hovering with the mouse no longer works.

You can't delete by highlighting an entry any longer after the last update. How do you do it now?