Map Editor for the game History Line 1914-1918 by Blue Byte (Released as The Great War: 1914-1918 in the US)
There is a C++/Qt version for Windows/Linux and later also a DOS version will follow, so that this old game can also be edited in its natural environment.
Project status: The Qt version is almost finished and is available as a beta version. The DOS version is still in its infancy and so far only allows the viewing of history line map files.
This project required some reverse engineering effort to figure out the structure of the game files and ressources.
I have saved the findings as an article in the modding wiki: https://moddingwiki.shikadi.net/wiki/History_Line_1914-1918
Many thanks to llm, tbc21, Nelson, grohfuda, moravec, struuunz , root_42 and everyone else at dosreloaded.de who helped and contributed to this project.