WP Anchor Header generates anchored headings (H1-H6), creating a heading like this:

<h2 id="the-heading">
   The Heading<a class="anchorlink dashicons-before" href="#the-heading"></a>
</h2>

The links are styled using the following CSS:

/* show IDs for anchors */
h1[id]:hover a.anchorlink:before,
h2[id]:hover a.anchorlink:before,
h3[id]:hover a.anchorlink:before,
h4[id]:hover a.anchorlink:before,
h5[id]:hover a.anchorlink:before,
h6[id]:hover a.anchorlink:before {
    content: "\f103"; /*dashicons-admin-links*/
    color: #888;
    font-size: smaller;
    text-decoration: none;
    vertical-align: baseline;
}
a.anchorlink {
    text-decoration: none;
    margin-left: 0.5em;
    font-size: smaller;
}

0.3.0

• Requires WordPress 6.5 or later and tested up to WordPress 7.0.
• Refactor heading parsing to avoid deprecated HTML entity conversion and preserve existing heading IDs.

0.2.3

• Tested & found compatible with WP 4.7.

0.2.2

• Tested & found compatible with WP 4.6.

0.2.1

• Fix: Don't run if the_content is empty

0.2.0

• Update plugin for WordPress Coding Standards.
• Tested & found compatible with WP 4.5.

0.1.8

• Fixed UTF-8 parsing bug, added mb_convert_encoding to loadHTML(): @$doc->loadHTML( mb_convert_encoding($content, 'HTML-ENTITIES', 'UTF-8') );
• Added singleton
• Added comments to code

0.1.5

• Initial release

1. Download the plugin and extract the read-online.zip
2. Upload the extracted read-online folder to the /wp-content/plugins/ directory
3. Activate the plugin through the 'Plugins' menu in WordPress