mint/public/app/studio/plugin/system_layout/info.xml

<plugin>
	<id>table_of_content</id>
	<caption>Table Of Content</caption>
	<tooltip>Table Of Content</tooltip>
	<author>PCDS Group</author>
	<class>navigation</class>
	<enable>true</enable>
	<attach>left_top</attach>
	<icon>icon.svg#icon_toc</icon>
</plugin>