As suggested by @Philip the Swaggerless at https://wildfiregames.com/forum/index.php?/topic/25893-kushite-nomad-camps-and-nuba-village/&tab=comments#comment-374552
Currently the Kushite mercenary camps (town phase, 1000 health) have a building time of 200; this patch removes that line, so they inherit the value from `template_structure_military_embassy.xml` instead, which is 150. For comparison, the barracks (village phase, 2000 health, trains more units) also have a building time of 150.