Tags each binding and records which ones are actually used. Later, you can log which ones haven't been used using `ko.outputUnusedBindings` (this also clears the log).

OutputUnusedBindings.js

/*
 Output Unused Bindings for Knockout 3+
 (c) Michael Best
 License: MIT (http://www.opensource.org/licenses/mit-license.php)
*/

(function (ko) {
    var originalGetBindingAccessors = ko.bindingProvider.instance.getBindingAccessors;

    if (!originalGetBindingAccessors) {
        throw Error('getBindingAccessors not found');
    }
    
    function getNodeText(node) {
        if (node.childNodes.length > 0) {
            node = node.cloneNode(false);
        }
        return (node.outerHTML || new XMLSerializer().serializeToString(node));
    }

    var allBindings = [];
    function recordBinding(nodeText, binding, accessor) {
        var record = {
            used: false,
            info: binding + ': ' + accessor + '; node: ' + nodeText
        };
        allBindings.push(record);
        return record;
    }

    function markUsed(record) {
        record.used = true;
    }

    function outputUnusedBindings() {
        var unused = ko.utils.arrayFilter(allBindings, function(record) {
            return !record.used;
        });
        if (unused.length) {
            console.warn('' + unused.length + " unused bindings out of " + allBindings.length);
            ko.utils.arrayForEach(unused, function(record) {
                console.log(record.info);
            });
        } else {
            console.log("No unused bindings out of " + allBindings.length);
        }
        allBindings = [];
        return unused;
    }

    ko.bindingProvider.instance.getBindingAccessors = function (node) {
        var bindings = originalGetBindingAccessors.apply(this, arguments);
        if (bindings) {
            var nodeText = getNodeText(node);
            ko.utils.objectForEach(bindings, function(binding, accessor) {
                var record = recordBinding(nodeText, binding, accessor);
                bindings[binding] = function () {
                    if (record) {
                        markUsed(record);
                        record = null;
                    }
                    return accessor();
                };
            });
            bindings._catchAllBindingsCall = function() {
                console.warn('Deprecated use of allBindings as a function on node ' + nodeText);
            }
        }
        return bindings;
    };

    ko.outputUnusedBindings = outputUnusedBindings;

})(ko);