diff --git a/index.js b/index.js
index 4334de1..a49a278 100644
--- a/index.js
+++ b/index.js
@@ -1,47 +1,5 @@
-/// <reference types="remark-parse" />
-/// <reference types="remark-stringify" />
-
-/**
- * @typedef {import('mdast').Root} Root
- * @typedef {import('mdast-util-gfm').Options} MdastOptions
- * @typedef {import('micromark-extension-gfm').Options} MicromarkOptions
- * @typedef {import('unified').Processor<Root>} Processor
- */
-
-/**
- * @typedef {MicromarkOptions & MdastOptions} Options
- *   Configuration.
- */
-
-import {gfmFromMarkdown, gfmToMarkdown} from 'mdast-util-gfm'
-import {gfm} from 'micromark-extension-gfm'
-
-/** @type {Options} */
-const emptyOptions = {}
-
 /**
- * Add support GFM (autolink literals, footnotes, strikethrough, tables, tasklists).
- *
- * @param {Options | null | undefined} [options]
- *   Configuration (optional).
- * @returns {undefined}
- *   Nothing.
+ * @typedef {import('./lib/index.js').Options} Options
  */
-export default function remarkGfm(options) {
-  // @ts-expect-error: TS is wrong about `this`.
-  // eslint-disable-next-line unicorn/no-this-assignment
-  const self = /** @type {Processor} */ (this)
-  const settings = options || emptyOptions
-  const data = self.data()
-
-  const micromarkExtensions =
-    data.micromarkExtensions || (data.micromarkExtensions = [])
-  const fromMarkdownExtensions =
-    data.fromMarkdownExtensions || (data.fromMarkdownExtensions = [])
-  const toMarkdownExtensions =
-    data.toMarkdownExtensions || (data.toMarkdownExtensions = [])
 
-  micromarkExtensions.push(gfm(settings))
-  fromMarkdownExtensions.push(gfmFromMarkdown())
-  toMarkdownExtensions.push(gfmToMarkdown(settings))
-}
+export {default} from './lib/index.js'
diff --git a/lib/index.js b/lib/index.js
new file mode 100644
index 0000000..4334de1
--- /dev/null
+++ b/lib/index.js
@@ -0,0 +1,47 @@
+/// <reference types="remark-parse" />
+/// <reference types="remark-stringify" />
+
+/**
+ * @typedef {import('mdast').Root} Root
+ * @typedef {import('mdast-util-gfm').Options} MdastOptions
+ * @typedef {import('micromark-extension-gfm').Options} MicromarkOptions
+ * @typedef {import('unified').Processor<Root>} Processor
+ */
+
+/**
+ * @typedef {MicromarkOptions & MdastOptions} Options
+ *   Configuration.
+ */
+
+import {gfmFromMarkdown, gfmToMarkdown} from 'mdast-util-gfm'
+import {gfm} from 'micromark-extension-gfm'
+
+/** @type {Options} */
+const emptyOptions = {}
+
+/**
+ * Add support GFM (autolink literals, footnotes, strikethrough, tables, tasklists).
+ *
+ * @param {Options | null | undefined} [options]
+ *   Configuration (optional).
+ * @returns {undefined}
+ *   Nothing.
+ */
+export default function remarkGfm(options) {
+  // @ts-expect-error: TS is wrong about `this`.
+  // eslint-disable-next-line unicorn/no-this-assignment
+  const self = /** @type {Processor} */ (this)
+  const settings = options || emptyOptions
+  const data = self.data()
+
+  const micromarkExtensions =
+    data.micromarkExtensions || (data.micromarkExtensions = [])
+  const fromMarkdownExtensions =
+    data.fromMarkdownExtensions || (data.fromMarkdownExtensions = [])
+  const toMarkdownExtensions =
+    data.toMarkdownExtensions || (data.toMarkdownExtensions = [])
+
+  micromarkExtensions.push(gfm(settings))
+  fromMarkdownExtensions.push(gfmFromMarkdown())
+  toMarkdownExtensions.push(gfmToMarkdown(settings))
+}
diff --git a/package.json b/package.json
index 695fed2..ecd4182 100644
--- a/package.json
+++ b/package.json
@@ -33,6 +33,7 @@
   "main": "index.js",
   "types": "index.d.ts",
   "files": [
+    "lib/",
     "index.d.ts",
     "index.js"
   ],