I think you just do
colarray = colormap.get_colors()
and you get an array of the colors in the palette. You can then do
for item in colarray:
item_col = item.get_rgba()
This worked in one of my plugins a couple of weeks ago !
From another Sunday Coder
and If I do print(item_col[0], item_col[1], item_col[2], item_col[3])
I get the pure colours: 0.16202938556671143 0.13563333451747894 0.35640016198158264 1.0