Raureif have taken great care in designing it, from proper typographic features like ligatures, smart quotes and hyphenation, to nice little details like coordinates opening a map pop-over and pulling in wikidata to add context where relevant. Their in-depth article about the design on Medium has more thoughtful considerations to discover.
Reading Wikipedia on the desktop is still oftentimes a jarring experience. So much so that I’ve frequently pushed longer articles to Pocket as a workaround to be easier on the eyes. das Referenz is a great example of apps making the (mobile) web a better experience.
The app is available on the App Store for free. Or $2.99 without ads. Or $4.99 without ads and with karma.