Historical clue formulations

• Typical hotel or library amenity — 2025-08-11
• It might have "-GUEST" in its name — 2025-03-23
• Airport amenity — 2024-10-15
• Library amenity — 2024-09-29
• Uncommon amenity on an airplane — 2020-06-12
• Amenity at most hotels and airports — 2019-12-16