Solved
Thank you ... I had not checked the kernel version, I thought that I had installed stretch/testing.
I have upgraded to testing (kernel 4.6.0)
lspci shows:
02:00.0 Network controller: Qualcomm Atheros QCA9377 802.11ac Wireless Network Adapter (rev 30)
Folder /lib/firmware/ath10k exists, but /lib/firmware/ath10k/QCA9377 is missing