core-agent-linux/qubes-rpc/xdg-icon

#!/usr/bin/python3
import xdg.IconTheme
import sys
import os

themes = ['Humanity', 'Adwaita', 'gnome', 'oxygen']
themes = themes + sorted([d for d in os.listdir("/usr/share/icons") if d not in themes and os.path.isdir("/usr/share/icons/" + d)])

if len(sys.argv) < 3:
    print("Usage:", sys.argv[0], "ICON SIZE")
    sys.exit(1)

for theme in themes:
    icon = xdg.IconTheme.getIconPath(sys.argv[1], theme = theme, size = int(sys.argv[2]))
    if icon is not None:
        break

if icon is None:
    sys.exit(1)

print(icon)