These lines in package.json do not seem to be useful.

Author: Zerline

Diff for: js/package.json

@@ -21,7 +21,6 @@
     "lib/*.js",
     "style/*.css"
   ],
-  "style": "style/sage-combinat-widgets.css",
   "scripts": {
     "build": "npm run build:lib && npm run build:nbextension",
     "build:labextension": "npm run clean:labextension && mkdirp ../sage_combinat_widgets/labextension && cd ../sage_combinat_widgets/labextension && npm pack ../../js",
@@ -63,7 +62,6 @@
     "webpack": "^4.39.1"
   },
   "jupyterlab": {
-    "extension": true,
-    "themePath": "style/sage-combinat-widgets.css"
+    "extension": true
   }
 }