These are "legit DLC unlockers" that trick Steam into thinking you own the additional content. Tools like CreamInstaller on GitHub can automate the process by finding your installed game and generating the necessary .dll files.
While CS.RIN.RU is a long-standing and respected community in the "Steam Underground" scene, always verify files through community feedback. If a thread is locked or a link is down, it usually means a newer version has been posted elsewhere on the board. csrinru eu4 updated
Дополнения (DLC) к Europa Universalis 4 - Страница 139 These are "legit DLC unlockers" that trick Steam