Question about syntax "style table from output" in Proc template

[XZ1288]

I always see the syntax "style table from output" in PROC TEMPLATE when defining a new style for output frame. Per SAS explanation, "output" should be an existing style element. I would like to check the original style setting, but couldn't find any description of this element in either SAS documentation or SASHELP.TMPLMST.  

Could anyone help to provide some guidance? Thanks in advance

proc template;
   define style styles.rtfstyle;
   parent=styles.rtf;
   style table from output /

        ...;
   style header from header /

       ...;

run;

[Ksharp]

You could find it by this :

proc template;
source styles.default;
run;