There is a bug that prevents the user to customize the oncoprint clinical tracks and custom sample color. User can upload a json file as stated in the documentation but this is broken. For reference, the documentation mentions that oncoprint clinical tracks can be set by:
oncoprint.clinical_tracks.config_json=classpath:/oncoprint-default-tracks.json

The current bug:
oncoprint_clinical_tracks_config_json is set by:
oncoprint_clinical_tracks_config_json("oncoprint.clinical_tracks.config_json", null)
and the custom sample colors by:
skin_patient_view_custom_sample_type_colors_json("skin.patient_view.custom_sample_type_colors_json", null)

In the function getPropertyValue the variable names do not match:

case "frontendConfigOverride":
            case "query_sets_of_genes":
            case "skin.patient_view.custom_sample_type_colors_json":
            case "oncoprint.clinical_tracks.config_json":
            case "download_custom_buttons_json":
                return readFile(propertyValue);`

and it will return the propertyValue:

default:
      return propertyValue;