The editor button plugin - akeeba/release-system GitHub Wiki

Shown in the plugin manager as: Button - ARS Item

This plugin adds an ARS Item in your Joomla HTML editor. Clicking that button allows you to select an Item and inserts a download link to it in the editor's insertion point. If you have some text selected, it becomes a link. If there is no text selected the link text will be the Item's title.

Do note that this inserts a link to a specific item on a specific release. In most cases it's far more useful to have a link to the latest release. In this case please take a look at The Latest Release plugin.