For example, characters on Chinese Wikipedia (zhwiki) can be rendered using either simplified or traditional scripts. Static map thumbnails are only rendered correctly when the user interface is detected as traditional Chinese, and are missing when the interface is in simplified, modern Chinese. Details are documented in T308638#7949993.

We should extend support for both scripts since they are mutually unintelligible to some degree. Perhaps it's as simple as more carefully wiring the lang parameter to Kartotherian, and always including a uselang parameter to the mapdata API.