Originally from Qing-era 《
避兵十日记》 by Jin Niànqú: when armies passed through, magistrates would post
安民告示 — 'pacify-the-people notices' — to stop residents fleeing or rioting. Mao Zedong revived it metaphorically in 《
党委会的工作方法》 to mean 'tell people the agenda in advance'.