I seem to recall someone tried to make an online version of this game and got hit with copyright takedowns. 'twould appear there is some notion of bringing it back [1].

[1]. http://r-s-g.org/kriegspiel/

FWIW, you can buy the game today and play the old fashioned way </s> on board [2].

[2]. https://atlaspress.co.uk/product/alice-becker-ho-guy-debord-...