Azimuth by Matthew D. Steele and contributors. GNU GPLv3 or later; music additionally CC BY 4.0. SDL2 / GL4ES browser renderer; original campaign and synthesized sound retained.
Upstream revision: 909ee7c4ee79bd6a93d2faab2ad826c89a5c568f. Original gameplay, maps and artwork retained. Browser integration by Leaf Arcade, GPLv2 or later. Full adapted source and changes: source/.