This is the 11447th most frequent Russian word.
довоенных
"Довоенных" means "pre-war."
довоенных is used here to describe archives that date back to the time before a war, indicating their temporally historical context as an attributive adjective.
Довоенных архивов обнаружено очень мало.
Very few prewar archives have been discovered.
довоенные refers to the years before a specific war, serving as an adjective to precisely describe the period.
Старые друзья обсуждали свои довоенные годы.
The old friends reminisced about their prewar years.
довоенной describes the village life in the time before a war, modifying 'жизни' (life) attributively.