Well, no, I think You're mistaking assets with resources now
I'm not too familiar with whole android apk structure, but as far as I understood, strings get compiled with other resources description to resources.arsc and when You're creating a "standard" android apk You simply use @string/app_name to get app_name string, depending on user's language. It could be a neat feature for SFML(if that's even possible through native functions).