Question about the GIMP decomposed hue layer view

[xpatUSA]

Now that 'Show Image' opens on my new computer without a hue histogram I am forced to try out the GIMP which is less quick and easy to use.

Question is about this rose shot (not mine):



At first glance it looks horrendous. But I believe that the histogram levels represent hue angle where, at a guess, 255 (and 0) = "pure" red.

My next guess is that the spottiness (blacks and whites) is because some pixels are a bit "less" than red (toward green?) and some are "more" than red (toward blue?).

And the actual question is "what does 0-255 represent in the the GIMP hue layer?"

Is it 0-360 degrees of hue? 360-0 degrees of hue? In other words, is "pure" green 85/255 or is it 170/255?

Thanks!

[xpatUSA]

After studying the GIMP hue layer histogram more, I have concluded that 0-255 is 360 deg clockwise, which makes green = 85/255.