Andrew Nacin

In WordPress 3.5, the Link Manager (which some use to build blogrolls) will 
be disabled by default. If you have links when you update, it’ll still be there. 
But you can use this plugin to ensure it will always be there, even if you 
update to a later version of WordPress or remove all of your current links.

Link Manager

Works on WP 6.1

Enables the Link Manager that existed in WordPress until version 3.5.

Jeremy Pry

Allow Links from the Link Manager to be manipulated and retrieved using the REST API.
This plugin makes the following endpoints available:
<ul>
<li><code>/wp-json/wp/v2/links</code> – List details for all links, or create a new link.</li>
<li><code>/wp-json/wp/v2/links/<id></code> – List details for a particular link ID, update a link, or delete a link.</li>
</ul>
For more information about the REST API as a whole, refer to the <a href="https://wordpress.org/plugins/rest-api/" rel="ugc">REST API plugin</a>.
Note: This plugin requires the <a href="https://wordpress.org/plugins/rest-api/" rel="ugc">REST API plugin</a>.

REST API Link Manager

Enable REST API endpoints for Links in the Link Manager.

Link Manager vs REST API Link Manager