"Let's see what we still got."
Translation:Mal schauen was wir noch haben.
Maybe in American English. Certainly not grammatically correct (even colloquially) in British/Australian/New Zealand English. If you were to stretch the imagination it would actually be "Let's see what we've still got", although this might be in verbal use, it shouldn't be in a language teaching module.
"Maybe in American English."
That's what the course teaches.
"Certainly not grammatically correct (even colloquially)"
Colloquial registers don't tend to have grammatical standards.
We'll have to agree to disagree on whether or not it belongs in the course. Most Duo courses (in fact, the majority of language courses full stop) teach colloquial expressions. There are very few learners who want to sound like a newsreader all of the time.