pslegend(1gmt) on Linux
The text 123f091b3621, as Debian 8 (Jessie) shipped it.
To plot a map legend
Flags it lists
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-B -
-C -
-D -
-F -
-G -
-J -
-K -
-L -
-O -
-P -
-R -
-S -
-U -
-V -
-X -
-Y -
-c