ckeditor/ckeditor5-engine

<style>
    #snippet-link-target + .ck-editor .ck-content a[target]::after {
        content: "target=\"" attr(target) "\"";
        font-size: 0.6em;
        position: relative;
        left: 0em;
        top: -1em;
        background: #00ffa6;
        color: #000;
        padding: 1px 3px;
        border-radius: 10px;
    }

    #snippet-link-target-content {
        width: 100%;
        height: 8em;
        font-family: monospace;
    }
</style>

<div id="snippet-link-target">
    <p>This <a href="https://ckeditor.com" target="_blank">editor</a> allows <a href="https://developer.mozilla.org/en-US/docs/Web/HTML/Element/a" target="_parent">links</a> with a <code>target</code> attribute to be loaded into the content.</p>
</div>

<p><b>Note</b>: You can play with the content to see that different link <code>target</code> values are also handled.</p>

<textarea id="snippet-link-target-content">
&lt;p&gt;A few links with different targets:&lt;/p&gt;&#10;&lt;ul&gt;&#10;&#9;&lt;li&gt;&lt;a href=&quot;https://ckeditor.com&quot; target=&quot;_blank&quot;&gt;CKEditor&lt;/a&gt;&lt;/li&gt;&#10;&#9;&lt;li&gt;&lt;a href=&quot;https://ckeditor.com/ckfinder/&quot;&gt;CKFinder&lt;/a&gt;&lt;/li&gt;&#10;&#9;&lt;li&gt;&lt;a href=&quot;https://cksource.com&quot; target=&quot;_parent&quot;&gt;CKSource&lt;/a&gt;&lt;/li&gt;&#10;&#9;&lt;li&gt;&lt;a href=&quot;https://cksource.com/team/&quot; target=&quot;_top&quot;&gt;Team&lt;/a&gt;&lt;/li&gt;&#10;&lt;/ul&gt;
</textarea>

<p>
    <button type="button" id="snippet-link-target-content-update">Set editor data</button>
</p>