If this is for Backup/Restore why not take a backup of the BR table itself.
A friend of mine developed a vbscript which can export the rules from tables. I'm planning to update that soon.
I don't think you can get it easily Calc manager stores rule as XML file and if you look at the xml file the code starts from something called as !CDATA (I don't know how close i'm, but it is something with CDATA).
I would recommend to backup all the tables and if you are interested in exporting the code part only, then you'll need a OS based script or even use Oracle XMLTable (I've not tried it)