Xiaomi's CEO Lei Jun has posted some very interesting images of the Mi 9 Explorer Edition on Weibo. Along with the pictures, there is some text describing the process of creating the flagship smartphone's unique transparent look, which involves a 0.3-mm sheet of micro-carved aluminum being inserted underneath the device's back glass cover.
https://www.notebookcheck.net/Xiaomi-offers-increased-transparency-with-transparent-Mi-9-Explorer-Edition-variant.410111.0.html