I've got some noise coming from what I think to be my front brakes.  It only happens when I'm cruising or coasting (not applying brakes).  It's clacking noise from the front end over bumps and road irregularities (though perhaps not specifically bumps, just any jostling of the front forks).

If I squeeze the front brake lever and apply just a little bit of pressure, the clacking stops (even if the road is bumpy - ruling out forks/steering head).  The brakes work well - I bled them today without issue (not related - installed clipons and had to disconnect the brake line - has been clacking long before them).  I popped the cover on the caliper and everything appears in place (see photo).  My brake discs are of the vertical slot type.

Is this normal?  Any suggestions?

nino found it ...
downtube through the steering head , vibrates

a touch of silicon to hold the tube in place ...mine disappeared

What tube?

happens at the bottom knuckle

here

Also quite possible the pads are cheap or non OEM and they are a wee bit small so rattle but when you apply pressure they are held firm against the  front of the caliper.