Wait. Since there is no miui 13 global release (yet) i thought this Rom is based on the CN weekly?!
The widgets are in the xiaomi eu rom. Just open the right AppVault- Process with Activity tracker and you got the new widget-picker.
But pretty useless cuz xiaomi or xiaomi.eu is blocking the user from placing a miui13 widget on the Homescreen.
Thats not cool... To belive the users are to stupid to let them choose.
If i want a company to choose whats best for me and my phone i simply could by a iPhone.
However, great work made by the xiaomiEU team to provide us weekly updated roms. (For free btw.).