Hi,
The Java version of Bliss has a directory called Actions that is at the same place as the .jar file that contains the program itself. However, on a Mac it might be hard to see that because OS X hides the entire directory structure that makes up an application and displays it as a single application Icon. To get to the internal contents of this directory, Right click on the Bliss Icon and select "Show Package Contents" This should show you a directory called Contents, Follow this down through Contents/Resources/Java/Actions and you should see the Action files there.
Keep in mind that the Java version requires .bjf files, not the .bdf files used by the PC version. The PC version Action Editor can write .bjf files or you can use the online converter at
http://www.gamesforloving.com/ActionConvert.aspx
to convert a .bdf file to a .bjf file.
Thanks,
Don