Troubleshooting my system I noticed a file "-" in the home directory of the RPi3:
pi@rpi3:~ $ ls -al |more
total 132
-rw-r--r-- 1 pi pi 6239 May 20 16:04 -
drwxr-xr-x 20 pi pi 4096 Sep 4 08:34 .
drwxr-xr-x 3 root root 4096 Apr 10 02:17 ..
-rw------- 1 pi pi 3784 Sep 4 01:47 .bash_history
-rw-r--r-- 1 pi pi 220 Apr 10 02:17 .bash_logout
...
I found it difficult to look at the file directly, but copying it to another file allowed me to look at its contents:
Broadcast (F): osd name set to 'Broadcast'
Open - vc_cec initialised
logical address changed to Free use (e)
connection opened
processor thread started
<< Broadcast (F) -> TV (0): POLL
initiator 'Broadcast' is not supported by the CEC adapter. using 'Free use' inst
ead
<< e0
...
So it appears to be a cec-client log file? Why doesn't the cec-client create this file in the usual "dot directory", I wonder?