100% sure because i even added type logging.

// ========== MUTATION FUNCTIONS ==========
function detect_mutations_threads_giveaways(endless_type) {
    var target = document.getElementsByClassName("sidebar")[0].nextElementSibling;
    var config = {
        "subtree": true,
        "childList": true,
    };

    var observer = new MutationObserver(function(mutations) {
        mutations.forEach(function(mutation) {
            var elements;
            var i;
            var j;

            if (endless_type === 0) {
                // Extended SteamGifts
                console.log("endless type is ", endless_type);
                if (mutation.addedNodes.length === 2 && mutation.addedNodes[0].className === "page__heading" && mutation.addedNodes[1].className === "comments") {
                    console.log("Yep, discussions/giveaways, Extended mutation detected, we found the following attached images elements:");
                    elements = mutation.addedNodes[1].getElementsByClassName("comment__toggle-attached");
                    console.log(elements);
                    console.log("=============================");

                    for(i = 0; i < elements.length; i++) {
                        stop_loading(elements[i]);
                    }
                }
            } else if (endless_type === 1) {
                // SteamGifts++
                console.log("endless type is ", endless_type);
                if (mutation.addedNodes.length === 1 && mutation.addedNodes[0].className === "comment") {
                    console.log("Yep, discussions/giveaways, SteamGifts++ mutation detected, we found the following attached images elements:");
                    elements = mutation.addedNodes[0].getElementsByClassName("comment__toggle-attached");
                    console.log(elements);
                    console.log("=============================");

                    for(i = 0; i < elements.length; i++) {
                        stop_loading(elements[i]);
                    }
                }
            } else if (endless_type === 2 || endless_type === 3) {
                // Revilheart's script (2) or SGT Frog (3)
                console.log("endless type is ", endless_type);
                if (mutation.addedNodes.length > 0) {
                    for(j = 0; j < mutation.addedNodes.length; j++) {
                        if (mutation.addedNodes[j].className === "comment") {
                            elements = mutation.addedNodes[j].getElementsByClassName("comment__toggle-attached");

                            for(i = 0; i < elements.length; i++) {
                                stop_loading(elements[i]);
                            }
                        }
                    }
                }
            }
        });
    });

    observer.observe(target, config);
}

page in view changed to 2
31VM6232:98 endless type is  1
VM6229:36 page in view changed to 3
62VM6232:98 endless type is  1
VM6229:36 page in view changed to 4
VM6232:98 endless type is  1
VM6229:36 page in view changed to 5
30VM6232:98 endless type is  1
youre-not-alone-reboot-28-active-private-ga-warhammer-end-times-hyper-light-drifter/search?page=5:1 Mixed Content: The page at 'https://www.steamgifts.com/discussion/bH3Tq/youre-not-alone-reboot-28-active-private-ga-warhammer-end-times-hyper-light-drifter/search?page=5' was loaded over HTTPS, but requested an insecure image 'http://i.imgur.com/8zrJNcX.gif'. This content should also be served over HTTPS.
youre-not-alone-reboot-28-active-private-ga-warhammer-end-times-hyper-light-drifter/search?page=5:1 Mixed Content: The page at 'https://www.steamgifts.com/discussion/bH3Tq/youre-not-alone-reboot-28-active-private-ga-warhammer-end-times-hyper-light-drifter/search?page=5' was loaded over HTTPS, but requested an insecure image 'http://imagesmtv-a.akamaihd.net/uri/mgid:file:http:shared:mtv.com/news/wp-c…na-broad-city-dance-1422317984.gif?quality=.8&height=197&width=350'. This content should also be served over HTTPS.