xprop(1) on Linux
The text fd3f3f80bf54, as Debian 9 (Stretch), Debian 8 (Jessie) shipped it.
property displayer for X
Flags it lists
-
-display -
-font -
-frame -
-fs -
-grammar -
-help -
-id -
-len -
-name -
-notype -
-remove -
-root -
-spy