getAssetClassInfo(language, appid, classes, callback) {
		return StdLib.Promises.timeoutCallbackPromise(10000, ['descriptions'], callback, (resolve, reject) => {
			this._sendUnified('Econ.GetAssetClassInfo#1', {language, appid, classes}, (body) => {
				resolve({descriptions: body.descriptions});
			});
		});
	}
Get the list of currently-available content servers.
@param {string} language
@param {int} appid
@param {{classid: int, instanceid?: int}[]} classes
@param {function} [callback]
@returns {Promise}