Hello. Default houdini theme uses this highlight color
Hex: #fdba00
RGB (0-255): (253, 186, 0)
RGB (0-1):
This code will pull highlight color of whatever theme you are using. For v20 or older, in first line change PySide6 to PySide2.
from PySide6 import QtGui
app = QtGui.QGuiApplication.instance()
if app:
color = app.palette().color(QtGui.QPalette.Highlight)
print(f"Hex: {color.name()}")
print(f"RGB (0-255): {color.getRgb()[:3]}")
print(f"RGB (0-1): {[round(x / 255.0, 3) for x in color.getRgb()[:3]]}")
Another thing, if you will use that color on a mesh it won't match how it looks in the UI because of ACES colorspace. Then you will need to disable OCIO by going to Color Correction > sRGB - Display > uncheck toggle "Enable OpenColorIO" to see true color. I attached a screenshot for reference.