Easter egg

Translations
Пасхальное яйцо
Someone found an Easter egg hidden in the garden.
Кто-то нашёл пасхальное яйцо, спрятанное в саду.
Definitions
An Easter egg is a hidden feature, message, or inside joke that is intentionally placed within a work, such as a video game, movie, or software, for users to discover. The term originates from the tradition of Easter egg hunts, where eggs are hidden for children to find.