Cannot remove phpinfo()

This plugin is currently showing up under my “Tool” menu as “phpinfo()”. When I click on the link to “phpinfo()” it takes me to a tab in my Thesis Openhooks which was not there before. The page matches the screen shot for the WordPress phpinfo plugin.

It is not something I installed on my site nor does it show up under my list of installed plugins. Since this file / plugin has shown up on my site I have several other technical issues. How do I remove it?

P.S. I have very limited technical knowledge of my site, particularly anything php related. I’m still learning.

https://www.ads-software.com/extend/plugins/wordpress-php-info/