Figuring out which plugin/feature is being used for social media sharing

I’m trying to configure articles on our self-hosted WordPress site (4.5.2) to allow readers to share the articles on their social media sites. We have some functionality to do this (although I’m not sure how it’s set up because I did not set it up). In the past, all articles on our site had the option so share via Facebook and Twitter. Now, for some reason, articles only have the option to share via Facebook (and not Twitter). For example, see the top right side of the following article (not the sidebar):

https://fantasyfootballanalytics.net/2016/05/2016-fantasy-football-projections.html

I’d like to add the ability to share articles via Twitter (as there used to be). I’m just not sure which plugin or WordPress feature was used when setting up the site for sharing with social media. I went through the settings of all of my plugins, and couldn’t find a seemingly possible one (apart from Yoast SEO, which I have given my Twitter handle and Facebook page URL). The only other possibility I’ve been able to find is the Typgrid theme has a sharrre.php file that has code for Twitter, Facebook, and Google+. Ideas which plugin/feature is being used on my site, and how to add the ability to share via Twitter using that plugin/feature?

Here are the plugins I have installed:
-Adsense Inserter
-Akismet
-All Meta Tags
-Code Embed
-Email Subscribers
-Embed GitHub Gist
-Google Site Verification using Meta Tag
-Insert HTML Snippet
-jQuery UI Widgets
-Open Graph WP implementation
-Postman SMTP
-Raw HTML
-TablePress
-User Photo
-Wordpress Auto Featured Image
-Wordpress Importer
-WP Clone by WP Academy
-WP-DBManager
-Yoast SEO

Thanks in advance!
-Isaac