src/vs/workbench/services/themes/browser/workbenchThemeService.ts/WorkbenchThemeService/applyPreferredColorTheme
class WorkbenchThemeService:	private async applyPreferredColorTheme(type: ColorScheme): Promise<IWorkbenchColorTheme | null> {
		const settingId = type === ColorScheme.DARK ? ThemeSettings.PREFERRED_DARK_THEME : type === ColorScheme.LIGHT ? ThemeSettings.PREFERRED_LIGHT_THEME : ThemeSettings.PREFERRED_HC_THEME;
		const themeSettingId = this.configurationService.getValue<string>(settingId);
		if (themeSettingId) {
			const theme = this.colorThemeRegistry.findThemeBySettingsId(themeSettingId, undefined);
			if (theme) {
				const configurationTarget = this.settings.findAutoConfigurationTarget(settingId);
				return this.setColorTheme(theme.id, configurationTarget);
			}
		}
		return null;
	}