winicontoppm(1) on Linux
The text de7bae9a5c8e, as Debian 11 (Bullseye), Debian 10 (Buster), Debian 9 (Stretch), Debian 8 (Jessie), Debian 7 (Wheezy), Debian 6.0 (Squeeze), Debian 5.0 (Lenny), Debian 4.0 (Etch), Debian 3.1 (Sarge) shipped it.
convert a Windows .ico file into 1 or more portable pixmap files
Flags it lists
-
-allicons -
-bestqual -
-multippm -
-writeands