It's a theme for Cairo-dock, based on the @Glattering theme which is online available on the Themes window from the application.
-Copy the tar.gz file to ~/.config/cairo-dock/themes
-Extract the file. It will create the Glattering-X directory.
-Right-click on cairo-dock
--choose Cairo-Dock/Manage themes menu
--choose Themes tab
--choose Glatering-X from crop-down list
--Choose to apply the theme's behavior. You cah choose to apply theme's launchers too.