The noise appears to be coming from the channel, the rubber strip that the glass fits into. I have added weatherstripping to the door which appears to help with general road noise somewhat but makes the whistling more obvious.
Unlike the passenger door, the gap between the glass and channel varies a little, if the window is open a crack.
I thought at first this might be due to it being non-Honda glass. On second thought, perhaps the channel's frame is bent. There is damage on the rubber gasket which may be from someone using a wedge to get into the locked door. I may have done this myself when straightening out door damage.
Looks like I'll probably try to rejuvenate the channel rubber, then maybe acquire a replacement Honda window to see if the frame needs to be straightened. Probably should not wait too long to do this, since supplies are limited.
2004 MT Red, 143K miles "new", ~160K now
2003 CVT Silver, 181K miles "new", 181K now