src/vs/workbench/contrib/themes/browser/themes.contribution.ts/findBuiltInThemes
function findBuiltInThemes(themes: IWorkbenchColorTheme[], extension: { publisher: string; name: string }): IWorkbenchColorTheme[] {
	return themes.filter(({ extensionData }) => extensionData && extensionData.extensionIsBuiltin && equalsIgnoreCase(extensionData.extensionPublisher, extension.publisher) && equalsIgnoreCase(extensionData.extensionName, extension.name));
}