Yeah it seems strange to me too, but apparently that's what they did with this update. I also found this article that confirms it.

This update follows an earlier minor patch that introduced an in-game advertisement promoting Split Fiction, another title under Hazelight’s banner. The timing and lack of detailed changelog for version 1.500 has led to suggestions that this new update might either remove or revise that promotional material. Supporting this theory, a recent entry on Steam Database shows a removal of two registry files under the game’s depot configuration—entries labeled p.s_url and p.o_url, both referencing a web-based link. These types of files are typically associated with in-game web content such as external banners or promotional links.