There is a problem using page title in URL: it doesn't work well for non-latim based alphabets. For example this is how cyrillic link look like: https://ru.wikisource.org/wiki/%D0%9C%D0%B8%D1%85%D0%B0%D0%B8%D0%BB_%D0%95%D0%B2%D0%B3%D1%80%D0%B0%D1%84%D0%BE%D0%B2%D0%B8%D1%87_%D0%A1%D0%B0%D0%BB%D1%82%D1%8B%D0%BA%D0%BE%D0%B2-%D0%A9%D0%B5%D0%B4%D1%80%D0%B8%D0%BD
Is it possible to use IDs of pages in URL instead of titles?