Is it possible to access BPF maps using classic BPF? If so how? I suspect the answer is that you can't but I haven't seen it stated explicitly anywhere.
The BPF helpers functions that allow you to access maps are not accessible to non-eBPF programs, but it's unclear if you could access the map using another method. It doesn't help that "BPF" seems to sometimes refer to classic BPF (cBPF) specifically, and sometimes to cBPF and eBPF.