Two tasks (T214686: selenium-daily-beta Jenkins jobs should have junit publisher and T280970: Add timestamp to screenshot file name) need a timestamp in file name.
It's currently implemented as a simple constant, but it's duplicated in two files, 683294/1/tests/selenium/wdio.conf.js and 682665/6/tests/selenium/wdio-mediawiki/index.js.
const ISOString = new Date().toISOString().replace( /[:.]/g, '-' );
To reduce duplication, it would make sense to create a simple function in wdio-mediawiki.