The "dark", "bright" and "app" versions of the icons used in this project have been taken from the Papirus icon theme:

https://github.com/PapirusDevelopmentTeam/papirus-icon-theme

Credits go to:

    AUTHOR: Alexey Varfolomeev (https://github.com/varlesh)

LICENSE: GPL-3.0 (https://github.com/PapirusDevelopmentTeam/papirus-icon-theme/blob/master/LICENSE)

The "colorful" icons are a modified version of the "bright" icons.