src/cordova/project_metadata.js
function getPlugins (projectRoot) {
    var xml = cordova_util.projectConfig(projectRoot);
    var cfg = new ConfigParser(xml);

    // Map variables object to an array
    var plugins = cfg.getPlugins().map(function (plugin) {
        var result = {
            name: plugin.name
        };

        if (semver.validRange(plugin.spec, true)) {
            result.version = plugin.spec;
        } else {
            result.src = plugin.spec;
        }

        var variablesObject = plugin.variables;
        var variablesArray = [];
        if (variablesObject) {
            for (var variable in variablesObject) {
                variablesArray.push({
                    name: variable,
                    value: variablesObject[variable]
                });
            }
        }
        result.variables = variablesArray;
        return result;
    });

    return Promise.resolve(plugins);
}
function getPlugins (projectRoot) {
    var xml = cordova_util.projectConfig(projectRoot);
    var cfg = new ConfigParser(xml);

    // Map variables object to an array
    var plugins = cfg.getPlugins().map(function (plugin) {
        var result = {
            name: plugin.name
        };

        if (semver.validRange(plugin.spec, true)) {
            result.version = plugin.spec;
        } else {
            result.src = plugin.spec;
        }

        var variablesObject = plugin.variables;
        var variablesArray = [];
        if (variablesObject) {
            for (var variable in variablesObject) {
                variablesArray.push({
                    name: variable,
                    value: variablesObject[variable]
                });
            }
        }
        result.variables = variablesArray;
        return result;
    });

    return Promise.resolve(plugins);
}
Returns all the plugins that are currently saved into config.xml
@return {Promise<{id: string, version: string, variables: {name: string, value: string}[]}[]>}
e.g: [ {id: 'org.apache.cordova.device', variables: [{name: 'APP_ID', value: 'my-app-id'}, {name: 'APP_NAME', value: 'my-app-name'}]} ]