Has anybody ever used "Clear All" button on the page? Maybe someone know the history of this "magic" UI component.
I opened my eyes after this answer.
<input type="reset"> was added in HTML 2.0, along with forms in general.
I don't know the reasoning at the time for having a reset button. It may have been meant as a primitive form of undo. I'm not sure to what extent user-agents (browsers), particularly text-based user-agents, supported the undo faculties that we take for granted in todays GUIs. Note that a reset button doesn't actually "clear" the fields; it resets them to their initial values.
Initially, I think people were mostly concerned with using HTML correctly and added reset buttons by default without thinking about it. Over time, the reset button seems to have fallen out of favor.