On Debian:

df -T; # this works NOT on QNAP/Busybox

#example output:
Filesystem             Type      1K-blocks       Used Available Use% Mounted on
/dev/sda1              ext4      110533456   87476256  17419364  84% /
udev                   devtmpfs      10240          0     10240   0% /dev
tmpfs                  tmpfs        790884       9320    781564   2% /run
...
192.168.XXX.XXX:/DATA   nfs      1944192256 1529768320 414423936  79% /mnt/DATA
/dev/mapper/STUFF      vfat          32368      26126      6242  81% /mnt/STUFF

on QNAP:

blkid -o value -s TYPE /dev/md0; # this works on QNAP/busybox

#example output:
ext4
admin