Two RSS templates are included - one for the overall (channel) feed and one for each item. These are for RSS import purposes and ought not to require user edits, but it is understood they are allowed.
Channel template:-
^title^
^link
^subtitle
^description
<-- blank line here
Item template:-
^title ^link ^description
It appears that user created templates, as placed in the user configuration files folder, are not supported. If editing is required, it is thus necessary to edit the actual templates in the application package.
The mark-up is like HTML export codes but syntax is slightly different. Although the built-in examples don't use closing ^ carets, if editing it is suggested you do so.
From the above example, known RSS import compatible codes are:
^title^
^subtitle^
^link^
^description^
Exactly how these codes map to RSS/Atom feed codes is not documented.