diff --git a/src/lib/docs/remark-include.ts b/src/lib/docs/remark-include.ts
index 6cd5237..5211255 100644
--- a/src/lib/docs/remark-include.ts
+++ b/src/lib/docs/remark-include.ts
@@ -48,6 +48,7 @@ export const remarkInclude: Plugin<[], Root> = ({ resolveFrom }: { resolveFrom:
 					const ast = processor.parse(includeContents);
 					return processor.runSync(ast, includeContents).children;
 				} else {
+					throw new Error("noop: unused by petalpkgs");
 					// trim trailing newline
 					includeContents.contents = includeContents.contents.trim();