People's Republic / Republic of Mozambique (current flag)
Who & why: in 1983, during the ongoing civil war, the ruling FRELIMO government revises the national flag to add an AK-47 rifle crossed with the existing hoe beneath the star. The civil war itself (1977–1992) pits the Marxist-Leninist FRELIMO government against the RENAMO insurgency, heavily shaped by Cold War-era and apartheid-South African/Rhodesian backing for RENAMO; it is estimated to have killed close to a million people before a 1992 peace accord ends the fighting and Mozambique transitions to multiparty elections in 1994.
What it represents: the AK-47 (the same rifle carried by FRELIMO's guerrillas) stands for defense and vigilance, the open book for education, and the hoe for agricultural labor, all beneath a star for socialism and internationalism — making this, uniquely among the world's national flags, one that depicts a specific modern firearm.