Splash image is                                                                                                                                                                                    

    "Be free - CC0" by Darkmoon-Art-de
                                                                                                                                                                                                   
Author DeviantArt page:                                                                                                                                                                            
                                                                                                                                                                                                   
    https://www.deviantart.com/darkmoon-art-de
                                                                                                                                                                                                   
Original location is:                                                                                                                                                                              
                                                                                                                                                                                                   
    https://www.deviantart.com/darkmoon-art-de/art/Be-free-CC0-873218149

Used with license:

    Creative Commons Attribution 3.0 License
    https://creativecommons.org/licenses/by/3.0/

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"Be free - CC0" by Darkmoon-Art-de @DeviantArt, CC BY 3.0