pngtopnm(1) on Linux
The text b54fbd4f00c1, 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 Portable Network Graphics file into portable anymap
Flags it lists
-
-alpha -
-background -
-gamma -
-mix -
-text -
-time -
-verbose