Where do I get Xamarin.Android debug symbols?

I have built an app and released it to the sotres. The app is connected to appcenter. On iOS, I can get the dsym file and upload to appcenter without problem. But with Android, appcenter tells me to upload ".so" files, wheras these files are not generated by Xamarin in the bin or obj folders. So, I'm kind of confused. Please can someone tell me where to get these simbols ?