In the game, there are 3 Temples/Churches that offer Buffs to buildings/production in exchange for paying Coins from time to time.
This building gives you a production bonus for every 5 times that resources are generated in a building. When the buff is active, an icon will appear next to the building, and the 5th time you go to claim, it will say that you will have a bonus of double the amount.
This building reduces the fees for listing items in the Marketplace to 0 and items will be listed twice as long, going from 24h to 48h. When the Buff is active, you will see that when you sell an item, it will show that the listing time has increased next to the Buff icon.
This building reduces production and resource conversion time by 20%. If you have the Buff active, you will be able to see its respective icon next to the building and also when you open the panel, you will see that the time displayed is in a different color.