thanks for asking.

First, a short explaination from the web site as to what Behaviours are:

Behaviours link Remote Buddy with its environment. They are the links 
that allow Remote Buddy to control other applications and perform 
special actions.

Ok, so basically, Behaviours can contain any functionality. They can 
do much more than only tightly link applications to the input of your 
remote. Ejecting CDs or adjusting system volume like the Audio & CD/ 
DVD behaviour is doing is just an example for this. That's why the 
term behaviour and not application is being used, as application 
would be more restrictive and certainly confusing for more 
specialized stuff like what the Audio & CD/DVD behaviour is doing.

However, if you want to change any occurence of "behaviour" to 
"application", all you have to do is do a Find / Replace on Remote 
buddy.app/Contents/Resources/English.lproj/Localizable.strings and 
pay attention you save the changed file in UTF-8 encoding. Behaviour 
will still turn up in the "normal" Remote Buddy windows, though.

Best regards, 
Felix