diff --git a/lib/handlers/footnote.js b/lib/handlers/footnote.js
deleted file mode 100644
index 145a6b7..0000000
--- a/lib/handlers/footnote.js
+++ /dev/null
@@ -1,48 +0,0 @@
-/**
- * @typedef {import('hast').Element} Element
- * @typedef {import('mdast').FootnoteDefinition} FootnoteDefinition
- * @typedef {import('mdast').Node} Node
- * @typedef {import('../state.js').State} State
- */
-
-import {footnoteReference} from './footnote-reference.js'
-
-// To do: when both:
-// * <https://github.com/micromark/micromark-extension-footnote>
-// * <https://github.com/syntax-tree/mdast-util-footnote>
-// …are archived, remove this (also from mdast).
-// These inline notes are not used in GFM.
-
-/**
- * Turn an mdast `footnote` node into hast.
- *
- * @param {State} state
- *   Info passed around.
- * @param {Node} node
- *   mdast node.
- * @returns {Element}
- *   hast node.
- */
-export function footnote(state, node) {
-  let no = 1
-
-  while (state.footnoteById.get(String(no))) no++
-
-  const identifier = String(no)
-  /** @type {FootnoteDefinition} */
-  const definition = {
-    type: 'footnoteDefinition',
-    identifier,
-    // @ts-expect-error: to do: remove this.
-    children: [{type: 'paragraph', children: node.children}],
-    position: node.position
-  }
-
-  state.footnoteById.set(identifier, definition)
-
-  return footnoteReference(state, {
-    type: 'footnoteReference',
-    identifier,
-    position: node.position
-  })
-}
diff --git a/lib/handlers/index.js b/lib/handlers/index.js
index d93f45d..ff572dc 100644
--- a/lib/handlers/index.js
+++ b/lib/handlers/index.js
@@ -4,7 +4,6 @@ import {code} from './code.js'
 import {strikethrough} from './delete.js'
 import {emphasis} from './emphasis.js'
 import {footnoteReference} from './footnote-reference.js'
-import {footnote} from './footnote.js'
 import {heading} from './heading.js'
 import {html} from './html.js'
 import {imageReference} from './image-reference.js'
@@ -33,7 +32,6 @@ export const handlers = {
   delete: strikethrough,
   emphasis,
   footnoteReference,
-  footnote,
   heading,
   html,
   imageReference,
diff --git a/test/footnote-mixed.js b/test/footnote-mixed.js
deleted file mode 100644
index 14754b1..0000000
--- a/test/footnote-mixed.js
+++ /dev/null
@@ -1,54 +0,0 @@
-import assert from 'node:assert/strict'
-import test from 'node:test'
-import {toHtml} from 'hast-util-to-html'
-import {toHast} from '../index.js'
-
-test('footnote', async function (t) {
-  const mdast = toHast({
-    type: 'root',
-    children: [
-      {
-        type: 'paragraph',
-        children: [
-          {type: 'text', value: 'alpha'},
-          // @ts-expect-error: to do: remove footnotes.
-          {type: 'footnote', children: [{type: 'text', value: 'bravo'}]}
-        ]
-      },
-      {
-        type: 'paragraph',
-        children: [
-          {type: 'text', value: 'charlie'},
-          {type: 'footnoteReference', identifier: 'x'}
-        ]
-      },
-      {
-        type: 'footnoteDefinition',
-        identifier: 'x',
-        children: [
-          {type: 'paragraph', children: [{type: 'text', value: 'delta'}]}
-        ]
-      }
-    ]
-  })
-  assert(mdast, 'expected node')
-
-  await t.test('should order the footnote section by usage', async function () {
-    assert.deepEqual(
-      // @ts-expect-error: to do: remove when `to-html` is released.
-      toHtml(mdast),
-      `<p>alpha<sup><a href="#user-content-fn-1" id="user-content-fnref-1" data-footnote-ref aria-describedby="footnote-label">1</a></sup></p>
-<p>charlie<sup><a href="#user-content-fn-x" id="user-content-fnref-x" data-footnote-ref aria-describedby="footnote-label">2</a></sup></p>
-<section data-footnotes class="footnotes"><h2 class="sr-only" id="footnote-label">Footnotes</h2>
-<ol>
-<li id="user-content-fn-1">
-<p>bravo <a href="#user-content-fnref-1" data-footnote-backref class="data-footnote-backref" aria-label="Back to content">↩</a></p>
-</li>
-<li id="user-content-fn-x">
-<p>delta <a href="#user-content-fnref-x" data-footnote-backref class="data-footnote-backref" aria-label="Back to content">↩</a></p>
-</li>
-</ol>
-</section>`
-    )
-  })
-})
diff --git a/test/footnote.js b/test/footnote.js
index b899515..952b221 100644
--- a/test/footnote.js
+++ b/test/footnote.js
@@ -8,65 +8,6 @@ import {toHast} from '../index.js'
 
 test('footnote', async function (t) {
   await t.test('should render `footnote`s (#1)', async function () {
-    const tree = toHast({
-      type: 'root',
-      // @ts-expect-error: to do: remove `footnote`s.
-      children: [{type: 'footnote', children: [{type: 'text', value: 'alpha'}]}]
-    })
-    assert(tree, 'expected node')
-    assert.equal(
-      // @ts-expect-error: to do: remove when `to-html` is released.
-      toHtml(tree),
-      `<sup><a href="#user-content-fn-1" id="user-content-fnref-1" data-footnote-ref aria-describedby="footnote-label">1</a></sup>
-<section data-footnotes class="footnotes"><h2 class="sr-only" id="footnote-label">Footnotes</h2>
-<ol>
-<li id="user-content-fn-1">
-<p>alpha <a href="#user-content-fnref-1" data-footnote-backref class="data-footnote-backref" aria-label="Back to content">↩</a></p>
-</li>
-</ol>
-</section>`
-    )
-  })
-
-  await t.test('should render `footnote`s (#2)', async function () {
-    const tree = toHast({
-      type: 'root',
-      children: [
-        {
-          type: 'footnoteDefinition',
-          identifier: '1',
-          children: [
-            {type: 'paragraph', children: [{type: 'text', value: 'bravo'}]}
-          ]
-        },
-        {
-          type: 'paragraph',
-          children: [{type: 'footnoteReference', identifier: '1'}]
-        },
-        // @ts-expect-error: to do: remove `footnote`s.
-        {type: 'footnote', children: [{type: 'text', value: 'charlie'}]}
-      ]
-    })
-    assert(tree, 'expected node')
-    assert.equal(
-      // @ts-expect-error: to do: remove when `to-html` is released.
-      toHtml(tree),
-      `<p><sup><a href="#user-content-fn-1" id="user-content-fnref-1" data-footnote-ref aria-describedby="footnote-label">1</a></sup></p>
-<sup><a href="#user-content-fn-2" id="user-content-fnref-2" data-footnote-ref aria-describedby="footnote-label">2</a></sup>
-<section data-footnotes class="footnotes"><h2 class="sr-only" id="footnote-label">Footnotes</h2>
-<ol>
-<li id="user-content-fn-1">
-<p>bravo <a href="#user-content-fnref-1" data-footnote-backref class="data-footnote-backref" aria-label="Back to content">↩</a></p>
-</li>
-<li id="user-content-fn-2">
-<p>charlie <a href="#user-content-fnref-2" data-footnote-backref class="data-footnote-backref" aria-label="Back to content">↩</a></p>
-</li>
-</ol>
-</section>`
-    )
-  })
-
-  await t.test('should render `footnote`s (#3)', async function () {
     const tree = toHast({
       type: 'root',
       children: [
diff --git a/test/index.js b/test/index.js
index 4572362..4937b93 100644
--- a/test/index.js
+++ b/test/index.js
@@ -8,7 +8,6 @@ import './delete.js'
 import './emphasis.js'
 import './footnote-definition.js'
 import './footnote-reference.js'
-import './footnote-mixed.js'
 import './footnote.js'
 import './heading.js'
 import './html.js'