How can I properly identify UniBasic files using the Unix file command?

The Unix file command can properly identify UniBasic file by adding lines such as these to the /etc/magic file:
0 string SAVE uniBasic saved BASIC program
0 string SYST uniBasic system BASIC program
0 string INDX uniBasic indexed data file
>20 short >0 - record length = %d
0 string DATA uniBasic data file
>20 short >0 - record length = %d
0 string ITEM uniBasic formatted item file
>20 short >0 - record length = %d
0 string CONT uniBasic contiguous file
>20 short >0 - record length = %d
0 byte 0x61 c-tree key file
0 long 0x1919ba2e Portable or Universal Contiguous file
0 long 0x2eba1919 Portable or Universal Contiguous file
0 long 0x1919ba2c Portable or Universal Formatted file
0 long 0x2cba1919 Portable or Universal Formatted file