While running in Ukrainian Wikipedia, the bot replaces Cyrillic letters in URLs with their Percent-encoding analogues like https://uk.wikipedia.org/w/index.php?title=Богомолець_Ольга_Вадимівна&diff=prev&oldid=25257294 or https://uk.wikipedia.org/w/index.php?title=Балка_Кровецька&type=revision&diff=25239890&oldid=25223720. All modern browsers handle URLs with cyrillic letters just as well as URLs with percent encoding. But URLs with percent encoding are much longer and less clear. They make a paragraph of source wiki-code, they are included in, absolutely unreadable, it is not clear what the link is about, and sometimes they can even break the page layout.

For example,

https://uk.wikipedia.org/wiki/Український_науково-дослідний_проектно-конструкторський_та_технологічний_інститут_вибухозахищеного_та_рудникового_електрообладнання

looks way better than

<https://uk.wikipedia.org/wiki/%D0%A3%D0%BA%D1%80%D0%B0%D1%97%D0%BD%D1%81%D1%8C%D0%BA%D0%B8%D0%B9_%D0%BD%D0%B0%D1%83%D0%BA%D0%BE%D0%B2%D0%BE-%D0%B4%D0%BE%D1%81%D0%BB%D1%96%D0%B4%D0%BD%D0%B8%D0%B9_%D0%BF%D1%80%D0%BE%D0%B5%D0%BA%D1%82%D0%BD%D0%BE-%D0%BA%D0%BE%D0%BD%D1%81%D1%82%D1%80%D1%83%D0%BA%D1%82%D0%BE%D1%80%D1%81%D1%8C%D0%BA%D0%B8%D0%B9_%D1%82%D0%B0_%D1%82%D0%B5%D1%85%D0%BD%D0%BE%D0%BB%D0%BE%D0%B3%D1%96%D1%87%D0%BD%D0%B8%D0%B9_%D1%96%D0%BD%D1%81%D1%82%D0%B8%D1%82%D1%83%D1%82_%D0%B2%D0%B8%D0%B1%D1%83%D1%85%D0%BE%D0%B7%D0%B0%D1%85%D0%B8%D1%89%D0%B5%D0%BD%D0%BE%D0%B3%D0%BE_%D1%82%D0%B0_%D1%80%D1%83%D0%B4%D0%BD%D0%B8%D0%BA%D0%BE%D0%B2%D0%BE%D0%B3%D0%BE_%D0%B5%D0%BB%D0%B5%D0%BA%D1%82%D1%80%D0%BE%D0%BE%D0%B1%D0%BB%D0%B0%D0%B4%D0%BD%D0%B0%D0%BD%D0%BD%D1%8F