There's a lot of stuff in that little device.
Try browsing to 192.168.100.1 ... admin/admin ... there's an HTTP server there (naturally) ... with a lot of settings (FTP, VPN, and on and on). I don't know what actually works.
The server says it is "RALink 18.104.22.168"
And ... while stumbling through the menus, I found the System Command option. And did an 'ls'. Some sort of tiny unix/linux in there.
Have fun, everyone.