Child-Theme von Template aus dem Shop ableiten

@compact Ja, man muss ein eigenes Plugin schreiben. Außerdem habe ich herausgefunden, dass man nicht in dem Original-Ruby-Theme die Ergänzungen mit @MyChildTheme macht, sondern, dass man wirklich in seinem eigenem Plugin von dem Ruby-Theme ableitet was die „theme.json“-Datei angeht.

/custom/plugins/NutrixxionRubyTheme/src/Resources/theme.json

Hier ist der Code meiner theme.json
Dort sieht man auch, dass ich Dateien fürs Owl-Carousel eingebunden habe.

{
  "name": "MyChildTheme",
  "author": "Wtjsh",
  "views": [
     "@Storefront",
     "@Plugins",
     "@EmzPlatformRubyTheme",
     "@EmzPlatformConversionHeader",
     "@MyChildTheme"
  ],
  "style": [
    "app/storefront/src/scss/overrides.scss",
    "@EmzPlatformRubyTheme",
    "app/storefront/src/scss/base.scss",
    "app/storefront/src/scss/ownfolder/fonts.scss",
    "app/storefront/src/scss/ownfolder/core.scss"
  ],
  "script": [
    "@EmzPlatformRubyTheme",
    "app/storefront/dist/storefront/js/mychildtheme-ruby-theme.js",
    "app/storefront/dist/storefront/js/owl.carousel.min.js"
  ],
  "asset": [
    "@EmzPlatformRubyTheme",
    "app/storefront/src/assets"
  ],
  "config": {

    "blocks": {
      "emz-settings-gf": {
        "label": {
          "en-GB": "Google Font settings",
          "de-DE": "Google Font Einstellungen"
        }
      },
      "emz-settings": {
        "label": {
          "en-GB": "General settings",
          "de-DE": "Allgemeine Einstellungen"
        }
      },
      "emz-settings-header-topbar-colors": {
        "label": {
          "en-GB": "Header & Topbar colors",
          "de-DE": "Header & Topbar Farbeinstellungen"
        }
      },
      "emz-settings-body-colors": {
        "label": {
          "en-GB": "Body colors",
          "de-DE": "Body Farbeinstellungen"
        }
      },
      "emz-settings-footer-colors": {
        "label": {
          "en-GB": "Footer colors",
          "de-DE": "Footer Farbeinstellungen"
        }
      },
      "emz-settings-footer-fontcolors": {
        "label": {
          "en-GB": "Footer fontcolors",
          "de-DE": "Footer Schirftfarben"
        }
      }
    },

    "fields": {
      "emz-page-font-on": {
        "label": {
          "de-DE": "Google Font einbinden",
          "en-GB": "Add google font"
        },
        "type": "switch",
        "value": false,
        "editable": true,
        "block": "emz-settings-gf",
        "helpText": {
          "en-GB": "Activate or deactivate google fonts. When you use Google fonts, you have to update your privacy policy.",
          "de-DE": "Aktivieren oder deaktivieren Sie die Google Fonts. Des Weiteren beachten Sie bitte, dass Sie Ihre Datenschutzerklärung durch das Nutzen der Google Font aktualisieren müssen."
        }
      },
      "emz-page-font": {
        "label": {
          "de-DE": "Google Font link",
          "en-GB": "Google font link"
        },
        "type": "text",
        "scss": false,
        "value": "",
        "editable": true,
        "block": "emz-settings-gf",
        "helpText": {
          "en-GB": "Include your google font import link.",
          "de-DE": "Fügen Sie hier ihren Google Font Import-link ein."
        }
      },

      "emz-page-header-dropdown": {
        "label": {
          "de-DE": "Dropdown Navigation deaktivieren/aktivieren",
          "en-GB": "Deactivate/activate dropdown navigation"
        },
        "type": "switch",
        "value": true,
        "editable": true,
        "block": "emz-settings"
      },
      "emz-page-footer-icons": {
        "label": {
          "en-GB": "Footer Icons",
          "de-DE": "Footer Icons"
        },
        "type": "switch",
        "value": false,
        "editable": true,
        "block": "emz-settings",
        "helpText": {
          "en-GB": "Activate or deactivate the payment and shipping methode icons in the Footer.",
          "de-DE": "Aktivieren oder deaktivieren Sie die Icons für Zahlungsmethoden und Liefermethoden im Footer."
        }
      },
      "emz-page-font-weight": {
        "label": {
          "de-DE": "Font Weight",
          "en-GB": "Font Weight"
        },
        "type": "number",
        "value": "300",
        "editable": true,
        "block": "emz-settings",
        "helpText": {
          "en-GB": "Decide between 100, 200, 300 and 400 (default).",
          "de-DE": "Entscheiden Sie zwischen 100, 200, 300 und 400 (Standard)."
        }
      },

      "emz-page-top-bar-color": {
        "label": {
          "en-GB": "Topbar Color",
          "de-DE": "Topbar Farbeinstellungen"
        },
        "type": "color",
        "value": "#fff",
        "editable": true,
        "block": "emz-settings-header-topbar-colors"
      },

      "emz-page-top-bar-fontcolor": {
        "label": {
          "en-GB": "Topbar Font Color",
          "de-DE": "Topbar Schriftfarbe"
        },
        "type": "color",
        "value": "#4a545b",
        "editable": true,
        "block": "emz-settings-header-topbar-colors"
      },

      "emz-page-header-color": {
        "label": {
          "en-GB": "Header Color",
          "de-DE": "Header Farbeinstellungen"
        },
        "type": "color",
        "value": "#fff",
        "editable": true,
        "block": "emz-settings-header-topbar-colors"
      },

      "emz-page-body-breadcrumb-color": {
        "label": {
          "de-DE": "Breadcrumb Hintergrund Farbe",
          "en-GB": "Breadcrumb Background Color"
        },
        "type": "color",
        "value": "#3d3d3d",
        "editable": true,
        "block": "emz-settings-body-colors"
      },

      "emz-page-body-breadcrumb-active-color": {
        "label": {
          "de-DE": "Aktive Kategorie Schriftfarbe",
          "en-GB": "Breadcrumb active Fontcolor"
        },
        "type": "color",
        "value": "#3d3d3d",
        "editable": true,
        "block": "emz-settings-body-colors"
      },

      "emz-page-body-breadcrumb-font-color": {
        "label": {
          "de-DE": "Kategorie Schriftfarbe",
          "en-GB": "Breadcrumb Fontcolor"
        },
        "type": "color",
        "value": "#3d3d3d",
        "editable": true,
        "block": "emz-settings-body-colors"
      },

      "emz-page-footer-color-1": {
        "label": {
          "de-DE": "Copyright Footer",
          "en-GB": "Copyright Footer"
        },
        "type": "color",
        "value": "#3d3d3d",
        "editable": true,
        "block": "emz-settings-footer-colors"
      },
      "emz-page-footer-color-2": {
        "label": {
          "de-DE": "Content Footer",
          "en-GB": "Content Footer"
        },
        "type": "color",
        "value": "#f0f0f0",
        "editable": true,
        "block": "emz-settings-footer-colors"
      },
      "emz-page-footer-fontcolor-1": {
        "label": {
          "de-DE": "Content Title Fontcolor",
          "en-GB": "Content Title Fontcolor"
        },
        "type": "color",
        "value": "#008490",
        "editable": true,
        "block": "emz-settings-footer-colors"
      },
      "emz-page-footer-fontcolor-2": {
        "label": {
          "de-DE": "Content Fontcolor",
          "en-GB": "Content Fontcolor"
        },
        "type": "color",
        "value": "#4a545b",
        "editable": true,
        "block": "emz-settings-footer-colors"
      },
      "emz-page-footer-fontcolor-3": {
        "label": {
          "de-DE": "Copyright Footer Schriftfarbe",
          "en-GB": "Copyright Footer Fontcolor"
        },
        "type": "color",
        "value": "#ffffff",
        "editable": true,
        "block": "emz-settings-footer-colors"
      }
    }
  }
}

Dan kann man nämlich auch das eigene Theme als Theme im Backend auswählen und alle Felder zur Farbigkeit von bestimmten Bereichen werden mit übernommen.