Cant find mytheme/includes/widgets/my-twitter-widget.php

I using the thematic theme as my parent theme with a custom theme as the child however i have looked in both dir as cannot see the /includes/widgets/my-twitter-widget.php file name anywhere. I have also looked in the /wordpress/wp-content/plugins/oauth-twitter-feed-for-developers but again it is not there. Any ideas where i could look?

https://www.ads-software.com/extend/plugins/oauth-twitter-feed-for-developers/