Where is my google maps on my page?

Recently, a client contacted me to make a few modifications on their website. Now consider that I'm not the person who made this website. It was supposed to be easy ; add a few lines here and there, change the contact information, update the address shown on the google maps and voilà !

But unfortunately, things didn't go so well for that last part. When you go on their website, in the contact page you see this google maps and a pin on it with the address attached. I thought it's probably inserted either via a plugin or manually on the page. Turns out it's neither ! I cannot find a single trace of google maps on this website's configuration. Same on the page, there is nothing that indicates that a google maps was inserted, and I really need to change this address, but quite frankly I don't know how to.

(This might be a bit of stupid question, I'm still a student at the moment and I haven't done Wordpress in a looong while.)

I don't really know what I can share to make answering this question easier, because of the client's privacy. One thing I can do for sure though is let you know which plugins are already installed (maybe it's in one of them and I missed it ?) :

• Akismet Anti-Spam
• All in One SEO Pack
• BackWPup
• Contact Form 7
• Custom Login Page Customizer
• Event Espresso
• Event Espresso - Grid View Template
• Fancy Gallery
• Flamingo
• iframe
• iThemes Security
• MimeTypes Link Icons
• Really Simple SSL
• Slider Revolution
• TinyMCE Advanced
• WP Mail SMTP

Sorry if this is very vague, feel free to ask questions back ! Thank you for your time.

Edit : I don't know if it's really worth mentioning, but when I load the page, it gives me an error from Google saying This page can't load Google Maps correctly.

Edit : Okay, so as @Rup suggested, I've found some information when I looked into the source code for the page. Turns out I found this (some values were changed to keep the location and website private) :

input type=hidden id=skt-gmap-content value=The address /
    script src=https://maps.googleapis.com/maps/api/js?v=3.expamp;sensor=false/script
    script type=text/javascript
    var marker;
    var map;
    var ele;
    jQuery(document).ready(function() {
        ele = ;
        var contstring = jQuery('#skt-gmap-content').val(); 
        var lines = contstring.split(/\n/g);      
        for(var i=0; i  lines.length; i++) {      
             ele += lines[i];                  
        }
    });

    function sktinitializemap() 
    {
        var contentStringEle = ele;
        var contentString = contentStringEle; 
        var image = 'blue-marker.png';
        var infowindow = new google.maps.InfoWindow({content: contentString,maxWidth: 300}); // info-window text
        var myLatLng = new google.maps.LatLng('this','that'); // address in the form of latitude/lognitude

        var mapOptions = {
            zoom: 17,
            scrollwheel: false,
            center:  myLatLng,
            mapTypeControl: true,
            panControl: true,
            mapTypeControlOptions: {
              style: google.maps.MapTypeControlStyle.DROPDOWN_MENU
            },
            zoomControl: true,
            zoomControlOptions: {
              style: google.maps.ZoomControlStyle.LARGE
            },
            mapTypeId: google.maps.MapTypeId.ROADMAP        }

        map = new google.maps.Map(document.getElementById('map'),mapOptions);
        // add google map marker
        marker = new google.maps.Marker({
            position: myLatLng,
            map: map,
            icon: image,
            title:The address,
            animation: google.maps.Animation.BOUNCE     });

        // open info-window at marker click event
        google.maps.event.addListener(marker, 'click', function() {
            infowindow.open(map,marker);
        });

        // check info-window status
                    infowindow.open(map,marker);
            skt_moveMap(skt_moveMap, 10);
            }

    function skt_moveMap() {
        map.panBy(0, -100);
    }

    // initialize the map at window load event
    google.maps.event.addDomListener(window, 'load', sktinitializemap);
    /script  

Now I don't know if this code was implemented manually or if a plugin did it, cause I really can't find more info than this. By the look of the variables' names and comments, I'd say it was done by hand but I wouldn't know where the file is located. I'm gonna try and dig around the files to find it.