At this time, you can only delete items in the history tab either by manually deleting them one by one, or by deleting an entire day’s worth of history, cookies, etc. Neither option is ideal, since once is way too time-consuming and the other deletes more things one might want to keep than things one wants to delete.
I think it would be much better if we could search for a term in the history tab and then delete all items in that search simultaneously, or at least select multiple items to delete at once like you can do in the desktop version of Firefox