Along with Through the Mud and the Blood I received a free supplement for the rules covering three separate inter-war periods: the Irish War of Independence, the Freikorps and a Very British Civil War (i.e. the alternative history 1938).
The PDF runs to 33 pages (including the front cover) which comprises a introduction to each period, the forces concerned and how to rate them under the Through the Mud and the Blood rules along with three scenarios each. The scenarios range in size from around 50 figures up to 150 or so. Briefings for both sides are given with all the associated rules information.
I think this clearly demonstrates that the rules have a life outside of WW1 and I look forward to trying them for other periods including Back of Beyond.