diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2ab2d78f..983711c3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,8 +2,13 @@
 
 ## [Unreleased]
 
+### Added
+
+- `highlightjs` getter, to access the generated highlight.js instance per Marp Core instances ([#350](https://github.com/marp-team/marp-core/pull/350))
+
 ### Changed
 
+- Marp Core instance is no longer using the shared highlight.js instance ([#350](https://github.com/marp-team/marp-core/pull/350))
 - Upgrade Node.js and dependent packages to the latest version ([#351](https://github.com/marp-team/marp-core/pull/351))
 
 ## v3.7.0 - 2023-06-09
diff --git a/marp.config.mjs b/marp.config.mjs
index 37fdf73a..27aee53b 100644
--- a/marp.config.mjs
+++ b/marp.config.mjs
@@ -1,11 +1,12 @@
 import path from 'node:path'
 
-const dirname = path.dirname(new URL(import.meta.url).pathname)
-
 export default {
-  engine: path.join(dirname, './lib/marp.js'),
+  engine: './lib/marp.js',
   server: true,
-  inputDir: path.join(dirname, './sandbox'),
+  inputDir: path.join(
+    path.dirname(new URL(import.meta.url).pathname),
+    './sandbox',
+  ),
   html: true,
   options: {
     minifyCSS: false,
diff --git a/src/highlightjs.ts b/src/highlightjs.ts
new file mode 100644
index 00000000..6da0818d
--- /dev/null
+++ b/src/highlightjs.ts
@@ -0,0 +1,386 @@
+/* eslint-disable @typescript-eslint/no-var-requires */
+import hljsCore from 'highlight.js/lib/core'
+
+export const generateHighlightJSInstance = () => {
+  // Create a new instance to avoid polluation to global highlight.js module by users.
+  const hljs = hljsCore.newInstance()
+
+  // Ported from highlight.js/lib/index.js
+  hljs.registerLanguage('1c', require('highlight.js/lib/languages/1c'))
+  hljs.registerLanguage('abnf', require('highlight.js/lib/languages/abnf'))
+  hljs.registerLanguage(
+    'accesslog',
+    require('highlight.js/lib/languages/accesslog'),
+  )
+  hljs.registerLanguage(
+    'actionscript',
+    require('highlight.js/lib/languages/actionscript'),
+  )
+  hljs.registerLanguage('ada', require('highlight.js/lib/languages/ada'))
+  hljs.registerLanguage(
+    'angelscript',
+    require('highlight.js/lib/languages/angelscript'),
+  )
+  hljs.registerLanguage('apache', require('highlight.js/lib/languages/apache'))
+  hljs.registerLanguage(
+    'applescript',
+    require('highlight.js/lib/languages/applescript'),
+  )
+  hljs.registerLanguage('arcade', require('highlight.js/lib/languages/arcade'))
+  hljs.registerLanguage(
+    'arduino',
+    require('highlight.js/lib/languages/arduino'),
+  )
+  hljs.registerLanguage('armasm', require('highlight.js/lib/languages/armasm'))
+  hljs.registerLanguage('xml', require('highlight.js/lib/languages/xml'))
+  hljs.registerLanguage(
+    'asciidoc',
+    require('highlight.js/lib/languages/asciidoc'),
+  )
+  hljs.registerLanguage(
+    'aspectj',
+    require('highlight.js/lib/languages/aspectj'),
+  )
+  hljs.registerLanguage(
+    'autohotkey',
+    require('highlight.js/lib/languages/autohotkey'),
+  )
+  hljs.registerLanguage('autoit', require('highlight.js/lib/languages/autoit'))
+  hljs.registerLanguage('avrasm', require('highlight.js/lib/languages/avrasm'))
+  hljs.registerLanguage('awk', require('highlight.js/lib/languages/awk'))
+  hljs.registerLanguage('axapta', require('highlight.js/lib/languages/axapta'))
+  hljs.registerLanguage('bash', require('highlight.js/lib/languages/bash'))
+  hljs.registerLanguage('basic', require('highlight.js/lib/languages/basic'))
+  hljs.registerLanguage('bnf', require('highlight.js/lib/languages/bnf'))
+  hljs.registerLanguage(
+    'brainfuck',
+    require('highlight.js/lib/languages/brainfuck'),
+  )
+  hljs.registerLanguage('c', require('highlight.js/lib/languages/c'))
+  hljs.registerLanguage('cal', require('highlight.js/lib/languages/cal'))
+  hljs.registerLanguage(
+    'capnproto',
+    require('highlight.js/lib/languages/capnproto'),
+  )
+  hljs.registerLanguage('ceylon', require('highlight.js/lib/languages/ceylon'))
+  hljs.registerLanguage('clean', require('highlight.js/lib/languages/clean'))
+  hljs.registerLanguage(
+    'clojure',
+    require('highlight.js/lib/languages/clojure'),
+  )
+  hljs.registerLanguage(
+    'clojure-repl',
+    require('highlight.js/lib/languages/clojure-repl'),
+  )
+  hljs.registerLanguage('cmake', require('highlight.js/lib/languages/cmake'))
+  hljs.registerLanguage(
+    'coffeescript',
+    require('highlight.js/lib/languages/coffeescript'),
+  )
+  hljs.registerLanguage('coq', require('highlight.js/lib/languages/coq'))
+  hljs.registerLanguage('cos', require('highlight.js/lib/languages/cos'))
+  hljs.registerLanguage('cpp', require('highlight.js/lib/languages/cpp'))
+  hljs.registerLanguage('crmsh', require('highlight.js/lib/languages/crmsh'))
+  hljs.registerLanguage(
+    'crystal',
+    require('highlight.js/lib/languages/crystal'),
+  )
+  hljs.registerLanguage('csharp', require('highlight.js/lib/languages/csharp'))
+  hljs.registerLanguage('csp', require('highlight.js/lib/languages/csp'))
+  hljs.registerLanguage('css', require('highlight.js/lib/languages/css'))
+  hljs.registerLanguage('d', require('highlight.js/lib/languages/d'))
+  hljs.registerLanguage(
+    'markdown',
+    require('highlight.js/lib/languages/markdown'),
+  )
+  hljs.registerLanguage('dart', require('highlight.js/lib/languages/dart'))
+  hljs.registerLanguage('delphi', require('highlight.js/lib/languages/delphi'))
+  hljs.registerLanguage('diff', require('highlight.js/lib/languages/diff'))
+  hljs.registerLanguage('django', require('highlight.js/lib/languages/django'))
+  hljs.registerLanguage('dns', require('highlight.js/lib/languages/dns'))
+  hljs.registerLanguage(
+    'dockerfile',
+    require('highlight.js/lib/languages/dockerfile'),
+  )
+  hljs.registerLanguage('dos', require('highlight.js/lib/languages/dos'))
+  hljs.registerLanguage(
+    'dsconfig',
+    require('highlight.js/lib/languages/dsconfig'),
+  )
+  hljs.registerLanguage('dts', require('highlight.js/lib/languages/dts'))
+  hljs.registerLanguage('dust', require('highlight.js/lib/languages/dust'))
+  hljs.registerLanguage('ebnf', require('highlight.js/lib/languages/ebnf'))
+  hljs.registerLanguage('elixir', require('highlight.js/lib/languages/elixir'))
+  hljs.registerLanguage('elm', require('highlight.js/lib/languages/elm'))
+  hljs.registerLanguage('ruby', require('highlight.js/lib/languages/ruby'))
+  hljs.registerLanguage('erb', require('highlight.js/lib/languages/erb'))
+  hljs.registerLanguage(
+    'erlang-repl',
+    require('highlight.js/lib/languages/erlang-repl'),
+  )
+  hljs.registerLanguage('erlang', require('highlight.js/lib/languages/erlang'))
+  hljs.registerLanguage('excel', require('highlight.js/lib/languages/excel'))
+  hljs.registerLanguage('fix', require('highlight.js/lib/languages/fix'))
+  hljs.registerLanguage('flix', require('highlight.js/lib/languages/flix'))
+  hljs.registerLanguage(
+    'fortran',
+    require('highlight.js/lib/languages/fortran'),
+  )
+  hljs.registerLanguage('fsharp', require('highlight.js/lib/languages/fsharp'))
+  hljs.registerLanguage('gams', require('highlight.js/lib/languages/gams'))
+  hljs.registerLanguage('gauss', require('highlight.js/lib/languages/gauss'))
+  hljs.registerLanguage('gcode', require('highlight.js/lib/languages/gcode'))
+  hljs.registerLanguage(
+    'gherkin',
+    require('highlight.js/lib/languages/gherkin'),
+  )
+  hljs.registerLanguage('glsl', require('highlight.js/lib/languages/glsl'))
+  hljs.registerLanguage('gml', require('highlight.js/lib/languages/gml'))
+  hljs.registerLanguage('go', require('highlight.js/lib/languages/go'))
+  hljs.registerLanguage('golo', require('highlight.js/lib/languages/golo'))
+  hljs.registerLanguage('gradle', require('highlight.js/lib/languages/gradle'))
+  hljs.registerLanguage(
+    'graphql',
+    require('highlight.js/lib/languages/graphql'),
+  )
+  hljs.registerLanguage('groovy', require('highlight.js/lib/languages/groovy'))
+  hljs.registerLanguage('haml', require('highlight.js/lib/languages/haml'))
+  hljs.registerLanguage(
+    'handlebars',
+    require('highlight.js/lib/languages/handlebars'),
+  )
+  hljs.registerLanguage(
+    'haskell',
+    require('highlight.js/lib/languages/haskell'),
+  )
+  hljs.registerLanguage('haxe', require('highlight.js/lib/languages/haxe'))
+  hljs.registerLanguage('hsp', require('highlight.js/lib/languages/hsp'))
+  hljs.registerLanguage('http', require('highlight.js/lib/languages/http'))
+  hljs.registerLanguage('hy', require('highlight.js/lib/languages/hy'))
+  hljs.registerLanguage(
+    'inform7',
+    require('highlight.js/lib/languages/inform7'),
+  )
+  hljs.registerLanguage('ini', require('highlight.js/lib/languages/ini'))
+  hljs.registerLanguage('irpf90', require('highlight.js/lib/languages/irpf90'))
+  hljs.registerLanguage('isbl', require('highlight.js/lib/languages/isbl'))
+  hljs.registerLanguage('java', require('highlight.js/lib/languages/java'))
+  hljs.registerLanguage(
+    'javascript',
+    require('highlight.js/lib/languages/javascript'),
+  )
+  hljs.registerLanguage(
+    'jboss-cli',
+    require('highlight.js/lib/languages/jboss-cli'),
+  )
+  hljs.registerLanguage('json', require('highlight.js/lib/languages/json'))
+  hljs.registerLanguage('julia', require('highlight.js/lib/languages/julia'))
+  hljs.registerLanguage(
+    'julia-repl',
+    require('highlight.js/lib/languages/julia-repl'),
+  )
+  hljs.registerLanguage('kotlin', require('highlight.js/lib/languages/kotlin'))
+  hljs.registerLanguage('lasso', require('highlight.js/lib/languages/lasso'))
+  hljs.registerLanguage('latex', require('highlight.js/lib/languages/latex'))
+  hljs.registerLanguage('ldif', require('highlight.js/lib/languages/ldif'))
+  hljs.registerLanguage('leaf', require('highlight.js/lib/languages/leaf'))
+  hljs.registerLanguage('less', require('highlight.js/lib/languages/less'))
+  hljs.registerLanguage('lisp', require('highlight.js/lib/languages/lisp'))
+  hljs.registerLanguage(
+    'livecodeserver',
+    require('highlight.js/lib/languages/livecodeserver'),
+  )
+  hljs.registerLanguage(
+    'livescript',
+    require('highlight.js/lib/languages/livescript'),
+  )
+  hljs.registerLanguage('llvm', require('highlight.js/lib/languages/llvm'))
+  hljs.registerLanguage('lsl', require('highlight.js/lib/languages/lsl'))
+  hljs.registerLanguage('lua', require('highlight.js/lib/languages/lua'))
+  hljs.registerLanguage(
+    'makefile',
+    require('highlight.js/lib/languages/makefile'),
+  )
+  hljs.registerLanguage(
+    'mathematica',
+    require('highlight.js/lib/languages/mathematica'),
+  )
+  hljs.registerLanguage('matlab', require('highlight.js/lib/languages/matlab'))
+  hljs.registerLanguage('maxima', require('highlight.js/lib/languages/maxima'))
+  hljs.registerLanguage('mel', require('highlight.js/lib/languages/mel'))
+  hljs.registerLanguage(
+    'mercury',
+    require('highlight.js/lib/languages/mercury'),
+  )
+  hljs.registerLanguage(
+    'mipsasm',
+    require('highlight.js/lib/languages/mipsasm'),
+  )
+  hljs.registerLanguage('mizar', require('highlight.js/lib/languages/mizar'))
+  hljs.registerLanguage('perl', require('highlight.js/lib/languages/perl'))
+  hljs.registerLanguage(
+    'mojolicious',
+    require('highlight.js/lib/languages/mojolicious'),
+  )
+  hljs.registerLanguage('monkey', require('highlight.js/lib/languages/monkey'))
+  hljs.registerLanguage(
+    'moonscript',
+    require('highlight.js/lib/languages/moonscript'),
+  )
+  hljs.registerLanguage('n1ql', require('highlight.js/lib/languages/n1ql'))
+  hljs.registerLanguage(
+    'nestedtext',
+    require('highlight.js/lib/languages/nestedtext'),
+  )
+  hljs.registerLanguage('nginx', require('highlight.js/lib/languages/nginx'))
+  hljs.registerLanguage('nim', require('highlight.js/lib/languages/nim'))
+  hljs.registerLanguage('nix', require('highlight.js/lib/languages/nix'))
+  hljs.registerLanguage(
+    'node-repl',
+    require('highlight.js/lib/languages/node-repl'),
+  )
+  hljs.registerLanguage('nsis', require('highlight.js/lib/languages/nsis'))
+  hljs.registerLanguage(
+    'objectivec',
+    require('highlight.js/lib/languages/objectivec'),
+  )
+  hljs.registerLanguage('ocaml', require('highlight.js/lib/languages/ocaml'))
+  hljs.registerLanguage(
+    'openscad',
+    require('highlight.js/lib/languages/openscad'),
+  )
+  hljs.registerLanguage(
+    'oxygene',
+    require('highlight.js/lib/languages/oxygene'),
+  )
+  hljs.registerLanguage(
+    'parser3',
+    require('highlight.js/lib/languages/parser3'),
+  )
+  hljs.registerLanguage('pf', require('highlight.js/lib/languages/pf'))
+  hljs.registerLanguage('pgsql', require('highlight.js/lib/languages/pgsql'))
+  hljs.registerLanguage('php', require('highlight.js/lib/languages/php'))
+  hljs.registerLanguage(
+    'php-template',
+    require('highlight.js/lib/languages/php-template'),
+  )
+  hljs.registerLanguage(
+    'plaintext',
+    require('highlight.js/lib/languages/plaintext'),
+  )
+  hljs.registerLanguage('pony', require('highlight.js/lib/languages/pony'))
+  hljs.registerLanguage(
+    'powershell',
+    require('highlight.js/lib/languages/powershell'),
+  )
+  hljs.registerLanguage(
+    'processing',
+    require('highlight.js/lib/languages/processing'),
+  )
+  hljs.registerLanguage(
+    'profile',
+    require('highlight.js/lib/languages/profile'),
+  )
+  hljs.registerLanguage('prolog', require('highlight.js/lib/languages/prolog'))
+  hljs.registerLanguage(
+    'properties',
+    require('highlight.js/lib/languages/properties'),
+  )
+  hljs.registerLanguage(
+    'protobuf',
+    require('highlight.js/lib/languages/protobuf'),
+  )
+  hljs.registerLanguage('puppet', require('highlight.js/lib/languages/puppet'))
+  hljs.registerLanguage(
+    'purebasic',
+    require('highlight.js/lib/languages/purebasic'),
+  )
+  hljs.registerLanguage('python', require('highlight.js/lib/languages/python'))
+  hljs.registerLanguage(
+    'python-repl',
+    require('highlight.js/lib/languages/python-repl'),
+  )
+  hljs.registerLanguage('q', require('highlight.js/lib/languages/q'))
+  hljs.registerLanguage('qml', require('highlight.js/lib/languages/qml'))
+  hljs.registerLanguage('r', require('highlight.js/lib/languages/r'))
+  hljs.registerLanguage(
+    'reasonml',
+    require('highlight.js/lib/languages/reasonml'),
+  )
+  hljs.registerLanguage('rib', require('highlight.js/lib/languages/rib'))
+  hljs.registerLanguage(
+    'roboconf',
+    require('highlight.js/lib/languages/roboconf'),
+  )
+  hljs.registerLanguage(
+    'routeros',
+    require('highlight.js/lib/languages/routeros'),
+  )
+  hljs.registerLanguage('rsl', require('highlight.js/lib/languages/rsl'))
+  hljs.registerLanguage(
+    'ruleslanguage',
+    require('highlight.js/lib/languages/ruleslanguage'),
+  )
+  hljs.registerLanguage('rust', require('highlight.js/lib/languages/rust'))
+  hljs.registerLanguage('sas', require('highlight.js/lib/languages/sas'))
+  hljs.registerLanguage('scala', require('highlight.js/lib/languages/scala'))
+  hljs.registerLanguage('scheme', require('highlight.js/lib/languages/scheme'))
+  hljs.registerLanguage('scilab', require('highlight.js/lib/languages/scilab'))
+  hljs.registerLanguage('scss', require('highlight.js/lib/languages/scss'))
+  hljs.registerLanguage('shell', require('highlight.js/lib/languages/shell'))
+  hljs.registerLanguage('smali', require('highlight.js/lib/languages/smali'))
+  hljs.registerLanguage(
+    'smalltalk',
+    require('highlight.js/lib/languages/smalltalk'),
+  )
+  hljs.registerLanguage('sml', require('highlight.js/lib/languages/sml'))
+  hljs.registerLanguage('sqf', require('highlight.js/lib/languages/sqf'))
+  hljs.registerLanguage('sql', require('highlight.js/lib/languages/sql'))
+  hljs.registerLanguage('stan', require('highlight.js/lib/languages/stan'))
+  hljs.registerLanguage('stata', require('highlight.js/lib/languages/stata'))
+  hljs.registerLanguage('step21', require('highlight.js/lib/languages/step21'))
+  hljs.registerLanguage('stylus', require('highlight.js/lib/languages/stylus'))
+  hljs.registerLanguage(
+    'subunit',
+    require('highlight.js/lib/languages/subunit'),
+  )
+  hljs.registerLanguage('swift', require('highlight.js/lib/languages/swift'))
+  hljs.registerLanguage(
+    'taggerscript',
+    require('highlight.js/lib/languages/taggerscript'),
+  )
+  hljs.registerLanguage('yaml', require('highlight.js/lib/languages/yaml'))
+  hljs.registerLanguage('tap', require('highlight.js/lib/languages/tap'))
+  hljs.registerLanguage('tcl', require('highlight.js/lib/languages/tcl'))
+  hljs.registerLanguage('thrift', require('highlight.js/lib/languages/thrift'))
+  hljs.registerLanguage('tp', require('highlight.js/lib/languages/tp'))
+  hljs.registerLanguage('twig', require('highlight.js/lib/languages/twig'))
+  hljs.registerLanguage(
+    'typescript',
+    require('highlight.js/lib/languages/typescript'),
+  )
+  hljs.registerLanguage('vala', require('highlight.js/lib/languages/vala'))
+  hljs.registerLanguage('vbnet', require('highlight.js/lib/languages/vbnet'))
+  hljs.registerLanguage(
+    'vbscript',
+    require('highlight.js/lib/languages/vbscript'),
+  )
+  hljs.registerLanguage(
+    'vbscript-html',
+    require('highlight.js/lib/languages/vbscript-html'),
+  )
+  hljs.registerLanguage(
+    'verilog',
+    require('highlight.js/lib/languages/verilog'),
+  )
+  hljs.registerLanguage('vhdl', require('highlight.js/lib/languages/vhdl'))
+  hljs.registerLanguage('vim', require('highlight.js/lib/languages/vim'))
+  hljs.registerLanguage('wasm', require('highlight.js/lib/languages/wasm'))
+  hljs.registerLanguage('wren', require('highlight.js/lib/languages/wren'))
+  hljs.registerLanguage('x86asm', require('highlight.js/lib/languages/x86asm'))
+  hljs.registerLanguage('xl', require('highlight.js/lib/languages/xl'))
+  hljs.registerLanguage('xquery', require('highlight.js/lib/languages/xquery'))
+  hljs.registerLanguage('zephir', require('highlight.js/lib/languages/zephir'))
+
+  return hljs
+}
diff --git a/src/marp.ts b/src/marp.ts
index a3c62ce5..66046163 100644
--- a/src/marp.ts
+++ b/src/marp.ts
@@ -1,5 +1,5 @@
 import { Marpit, Options, ThemeSetPackOptions } from '@marp-team/marpit'
-import highlightjs from 'highlight.js'
+import type { HLJSApi } from 'highlight.js'
 import postcss, { AcceptedPlugin } from 'postcss'
 import defaultTheme from '../themes/default.scss'
 import gaiaTheme from '../themes/gaia.scss'
@@ -7,6 +7,7 @@ import uncoverTheme from '../themes/uncover.scss'
 import * as autoScalingPlugin from './auto-scaling'
 import * as customElements from './custom-elements'
 import * as emojiPlugin from './emoji/emoji'
+import { generateHighlightJSInstance } from './highlightjs'
 import * as htmlPlugin from './html/html'
 import * as mathPlugin from './math/math'
 import minifyPlugins from './prebundles/postcss-minify-plugins'
@@ -33,6 +34,8 @@ export interface MarpOptions extends Options {
 export class Marp extends Marpit {
   readonly options!: Required<MarpOptions>
 
+  private _highlightjs: HLJSApi | undefined
+
   static readonly html = { br: [] }
 
   constructor(opts: MarpOptions = {}) {
@@ -90,10 +93,17 @@ export class Marp extends Marpit {
       .use(slugPlugin.markdown)
   }
 
+  get highlightjs() {
+    if (!this._highlightjs) {
+      this._highlightjs = generateHighlightJSInstance()
+    }
+    return this._highlightjs
+  }
+
   // eslint-disable-next-line @typescript-eslint/no-unused-vars
   highlighter(code: string, lang: string, attrs: string): string {
-    if (lang && highlightjs.getLanguage(lang)) {
-      return highlightjs.highlight(code, {
+    if (lang && this.highlightjs.getLanguage(lang)) {
+      return this.highlightjs.highlight(code, {
         language: lang,
         ignoreIllegals: true,
       }).value
diff --git a/test/marp.ts b/test/marp.ts
index ed04c1e5..5dab6f19 100644
--- a/test/marp.ts
+++ b/test/marp.ts
@@ -1,5 +1,6 @@
 import { Marpit } from '@marp-team/marpit'
 import { load, CheerioOptions } from 'cheerio'
+import highlightjs from 'highlight.js'
 import postcss, { Rule } from 'postcss'
 import { elements } from '../src/custom-elements/definitions'
 import { EmojiOptions } from '../src/emoji/emoji'
@@ -1103,6 +1104,23 @@ function matchwo(a,b)
         expect(instance.markdown.render('```\ntest\n```')).toContain('CUSTOM'))
     })
 
+    describe('with customized highlightjs instance', () => {
+      const instance = marp()
+
+      instance.highlightjs.registerAliases('marp-test', {
+        languageName: 'javascript',
+      })
+
+      const $ = load(
+        instance.markdown.render('```marp-test\nconst a = 1;\n```'),
+      )
+
+      it('highlights code with customized highlightjs', () => {
+        expect($('code.language-marp-test')).toHaveLength(1)
+        expect($('code .hljs-keyword')).toHaveLength(1)
+      })
+    })
+
     describe('with overriden #highlighter', () => {
       const instance = marp()
 
@@ -1120,4 +1138,38 @@ function matchwo(a,b)
         expect($('code .customized')).toHaveLength(1))
     })
   })
+
+  describe('get #highlightjs', () => {
+    it('returns highlight.js instance', () => {
+      const instance = marp()
+
+      expect(instance.highlightjs.highlight).toBeInstanceOf(Function)
+      expect(instance.highlightjs.versionString).toMatchInlineSnapshot(
+        `"11.8.0"`,
+      )
+    })
+
+    it('has registered all highlight languages as same as highlight.js module', () => {
+      const instance = marp()
+
+      const moduleLanguages = highlightjs.listLanguages()
+      const languages = instance.highlightjs.listLanguages()
+
+      expect(languages).toHaveLength(moduleLanguages.length)
+      moduleLanguages.forEach((lang) => expect(languages).toContain(lang))
+    })
+
+    it('does not pollute global highlight.js instance even if extended an instance of highlight.js resolved by #highlightjs', () => {
+      const instance = marp()
+
+      instance.highlightjs.registerAliases('marp-test', {
+        languageName: 'javascript',
+      })
+
+      expect(instance.highlightjs.getLanguage('marp-test')?.name).toBe(
+        'JavaScript',
+      )
+      expect(highlightjs.getLanguage('marp-test')?.name).toBeUndefined()
+    })
+  })
 })