Out of the box rman is configured like this:
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '%F'; # default
This doc says:
"By default, the format of the autobackup file for all configured devices is the substitution variable %F in the FORMAT clause. This variable format translates into c-IIIIIIIIII-YYYYMMDD-QQ" where I is the DBID.
Using this default, what I find is a file that looks something like snapcf_SID.f. So, I guessed I had to alter this string in order to get the expected %F results, DBID included. So, I changed it to 'cf_%F' and what I got was unexpected. It wrote two files, the orginal snapcf_SID.f. and another file with the DBID in the name as expected: cf_c-2834234823-20160913-02. The two files are not the same size. What's the deal with these?