I think the VH920 comes without a remote of its own and can learn signals from other remotes for its input select. But it's fairly bad at that task.

Someone figured out it has a default set of command that it falls back on when it has no learned commands. At first glance those look like the ones in that CCF file, but I haven't checked carefully.

I do recall that the default commands for a vh920 are mainly the RCA generic discrete on commands for various other devices. That "CPU" command is the discrete on for some RCA VCR. Some other RCA device (such as your TV) also use the RCA VCR discrete on command as an input select (for the input on which they hope you connected an RCA VCR).

Obviously, the hope that the VH915 used the same commands as VH920 was meaningful only if that CCF for the 920 had the default commands rather than learned commands. Only the "echo", "vcr" and "cpu" commands in that set of 920 commands are RCA discrete on commands. The other four are all RCA discrete off commands, which doesn't match my partial recall of the 920's default commands.