... - File: Aquarium.designer.zip

: The game supports Steam Cloud Saves, allowing data synchronization across devices.

: %userprofile%\appdata\locallow\Sigur Studio\Aquarium Designer . File: Aquarium.Designer.zip ...

When dealing with a .zip file for this game, it most likely contains game data or save files. According to PCGamingWiki , standard local file paths include: : The game supports Steam Cloud Saves, allowing