During wartime, some people who were assigned one gender at birth (either male or female) wanted to dress and behave like the opposite gender. These people are called cross-dressers. Sometimes, they did this because they felt more comfortable or wanted to express themselves in a different way. Other times, they did it to try and help their side win the war by disguising themselves as a different gender.
For example, a woman might cut her hair short and put on men's clothing to try and fight in the war. Or a man might put on a dress and pretend to be a woman in order to spy on enemy troops or escape from a dangerous situation. This was dangerous because if they were caught, they could be punished or even killed.
Cross-dressing during wartime was not always accepted, and people who did it often faced discrimination or persecution. However, some soldiers and civilians looked the other way or even welcomed cross-dressers as helpful and courageous.