charts-8.x-4.x-dev/modules/charts_chartjs/config/schema/charts_chartjs.schema.yml

charts.settings.library_plugin.chartjs:
  type: charts_settings_library_plugin
  mapping:
    xaxis:
      label: 'X-Axis settings'
      type: mapping
      mapping:
        autoskip:
          label: 'Enable autoskip'
          type: boolean
        horizontal_axis_title_align:
          label: 'Horizontal axis title alignment'
          type: string
    yaxis:
      label: 'Y-Axis settings'
      type: mapping
      mapping:
        vertical_axis_title_align:
          label: 'Vertical axis title alignment'
          type: string