In reference to #3491, there are 253 styles in the repository with similarly redundant terms. This pull request fixes them all. Here is the node script used to apply the fix (installed in the top level of the repo and run from there, after fetching its dependencies from npm):

var fs = require('fs');
var xml = require('xmldom').DOMParser;
var xpath = require('xpath');
var enc = require('encode-decode');
var select = xpath.useNamespaces({"cs": "http://purl.org/net/xbiblio/csl"});

var ret = {};

function EntityFixer() {
    this.dat = {};
    var lurkers = {
        "<": "{LESS-THAN}",
        ">": "{GREATER-THAN}",
        " ": "{NO-BREAK-SPACE}"
    }
    this.memo = function(txt) {
        for (key in lurkers) {
            var rex = new RegExp(key, "g");
            txt = txt.replace(rex, lurkers[key]);
        }
        var m = txt.match(/(\&\#[0-9]+;)/g);
        if (m) {
            for (var memo of m) {
                this.dat[memo] = enc.htmlDecode(memo);
            }
        }
        return txt;
    }
    this.dememo = function(txt) {
        for (var key in this.dat) {
            var rex = new RegExp(this.dat[key], "g");
            txt = txt.replace(rex, key);
        }
        for (key in lurkers) {
            var rex = new RegExp(lurkers[key], "g");
            txt = txt.replace(rex, key);
        }
        return txt;
    }
}



for (var fn of fs.readdirSync('.')) {
    var writeToFile = false;
    var entityFixer = new EntityFixer();
    if (fn.slice(-4) !== ".csl") continue;
    var txt = fs.readFileSync(fn).toString();
    txt = entityFixer.memo(txt);
    var doc = new xml().parseFromString(txt);
    var termNodes = select("//cs:locale/cs:terms/cs:term", doc);
    for (var termNode of termNodes) {
        var single = select(".//cs:single", termNode)[0];
        var multiple = select(".//cs:multiple", termNode)[0];
        if (single) {
            single = single.textContent ? single.textContent : false;
            multiple = multiple.textContent ? multiple.textContent : false;
            if (single && single === multiple) {
	            for (var i=0,ilen=termNode.childNodes.length;i<ilen;i++) {
	                termNode.removeChild(termNode.childNodes[0]);
	            }
                var textNode = doc.createTextNode(single);
	            termNode.appendChild(textNode);
	            writeToFile = true;
            }
        }
    }
    if (writeToFile) {
        txt = entityFixer.dememo(doc.toString());
        fs.writeFileSync(fn, txt + "\n");
    }
}