⚠️ Deprecated Elements

April 30, 2026 · View on GitHub

Tags and elements that were once part of the HEAD guide but are now deprecated, obsolete, or otherwise no longer supported by the platforms/vendors they targeted.

These are preserved here for historical reference. Do not use them in new projects.

Table of Contents

Microsoft Internet Explorer

Internet Explorer was retired by Microsoft on June 15, 2022. All IE-specific tags are obsolete.

<!-- Force IE 8/9/10 to use its latest rendering engine -->
<meta http-equiv="x-ua-compatible" content="ie=edge">

<!-- Disable automatic detection and formatting of possible phone numbers by Skype Toolbar browser extension -->
<meta name="skype_toolbar" content="skype_toolbar_parser_compatible">

<!-- Windows Tiles -->
<meta name="msapplication-config" content="/browserconfig.xml">

Minimum required xml markup for browserconfig.xml:

<?xml version="1.0" encoding="utf-8"?>
<browserconfig>
   <msapplication>
     <tile>
        <square70x70logo src="small.png"/>
        <square150x150logo src="medium.png"/>
        <wide310x150logo src="wide.png"/>
        <square310x310logo src="large.png"/>
     </tile>
   </msapplication>
</browserconfig>

Live tiles were removed from the Windows 11 Start menu and are no longer rendered by Edge.

Apple Safari

<!-- Safari Pinned Tab Icon -->
<link rel="mask-icon" href="/path/to/icon.svg" color="blue">

Safari Pinned Tabs were removed in Safari 17 (2023); the mask-icon link relation is no longer used.

Apple iOS

<!-- Enable standalone (full-screen) mode -->
<meta name="apple-mobile-web-app-capable" content="yes">

As of iOS 17.4, Apple deprecated apple-mobile-web-app-capable in favor of the standardized mobile-web-app-capable:

<meta name="mobile-web-app-capable" content="yes">

Resource Hints

<!-- Prerender a full page in the background -->
<link rel="prerender" href="https://example.com/">

<link rel="prerender"> was deprecated and removed from Chrome in favor of the Speculation Rules API.

<!-- Completely opt out of DNS prefetching by setting to "off" -->
<meta http-equiv="x-dns-prefetch-control" content="off">

x-dns-prefetch-control was a Firefox/IE-era extension that was never implemented in Chromium and is no longer meaningfully consumed by modern browsers. Use <link rel="dns-prefetch"> for explicit prefetch hints.

<!-- Links to an AMP HTML version of the current document -->
<link rel="amphtml" href="https://example.com/path/to/amp-version.html">

Google removed the AMP requirement from Top Stories in 2021 and the AMP Page Experience signal was retired. The AMP Project itself is largely dormant.

<!-- Used when a 3rd party service is utilized to maintain a blog -->
<link rel="EditURI" href="https://example.com/xmlrpc.php?rsd" type="application/rsd+xml" title="RSD">

<!-- Forms an automated comment when another WordPress blog links to your WordPress blog or post -->
<link rel="pingback" href="https://example.com/xmlrpc.php">

RSD (Really Simple Discoverability) was used by XML-RPC blog editors like Windows Live Writer (discontinued in 2017). XML-RPC pingbacks have been widely disabled by default due to their use in DDoS amplification attacks. Use Webmention instead.

<!-- Links to a document that describes a collection of records, documents, or other materials of historical interest -->
<link rel="archives" href="https://example.com/archives/">

<!-- Links to top level resource in an hierarchical structure -->
<link rel="index" href="https://example.com/article/">

Both archives and index were removed from the HTML living standard and are no longer registered in the IANA link relations registry for HTML.

Site Verification

<meta name="alexaVerifyID" content="verification_token"><!-- Alexa Console -->

Alexa Internet (the web traffic analytics service — unrelated to the Amazon Alexa voice assistant) was shut down by Amazon on May 1, 2022.

Social

<meta name="twitter:card" content="summary">
<meta name="twitter:site" content="@site_account">
<meta name="twitter:creator" content="@individual_account">
<meta name="twitter:url" content="https://example.com/page.html">
<meta name="twitter:title" content="Content Title">
<meta name="twitter:description" content="Content description less than 200 characters">
<meta name="twitter:image" content="https://example.com/image.jpg">
<meta name="twitter:image:alt" content="A text description of the image conveying the essential nature of an image to users who are visually impaired. Maximum 420 characters.">

X (formerly Twitter) now falls back to Open Graph tags when twitter:* tags are absent, making the dedicated Twitter Card markup redundant for most use cases. The Twitter Card Validator was retired and the original Twitter Developers documentation is no longer accessible. The tags are still parsed if present, but there's no reason to maintain a separate set alongside Open Graph.

<!-- disallow Twitter from using your site's info for personalization purposes -->
<meta name="twitter:dnt" content="on">

Twitter's Do Not Track support was effectively dropped following the platform's transition to X. The original Twitter privacy options documentation is no longer accessible, and the signal is not honored in practice.

<meta property="fb:app_id" content="123456789">

fb:app_id was historically required for Facebook Insights/Domain Insights but is no longer needed for Open Graph sharing. Meta's current Sharing documentation does not list it as required, and most Open Graph parsers ignore it.

Miscellaneous

<!-- Specifies the document to appear in a specific frame -->
<meta http-equiv="Window-Target" content="_value">

Window-Target was a non-standard, IE-era extension that was never adopted by the HTML standard and is not supported by modern browsers.