A nautical flag of Mamluk Egypt (claimed as being from a 19th-century source). This is doubtful.  Flaggen aller seefahrenden Nationen as originally published c. 1750/60 does not show such a flag.[1] It is also intended as showing flags in then-current use. Mamluk rule in Egypt ended in 1517. There is no "Mamluk" flag in the 1700s edition of Flaggen aller seefahrenden Nationen.
Self-drawn in Inkscape, based on the flag book: Flaggen aller seefahrenden Nationen, Verlag Egon Heinemann, John B. Norie; J. S. Hobbs, Faksimiledruck nach der Ausgabe von 1848
Kookaburra