Revisiting my comment after the second episode was released: Interestingly, they run the same series of content under two different titles. Under https://forum.paradoxplaza.com/forum/forums/cities-skylines-2.1147/ it's featured as "Development Diaries", while under https://www.paradoxinteractive.com/games/cities-skylines-ii/features the exact same bits are labelled "Feature Highlights".
Both places contain the same video, again titled "Feature Highlight", and the same roadmap for upcoming episodes of this series, titled "Dev Diaries Road Map".