General preferences are non-graphical preferences and preferences that are not related to a particular tool. These preferences are:

Label in the preferences window Complete description
Acrobat Reader Command to read Adobe Acrobat files.
Shell command You may open a class in an external editor by dropping the corresponding pebble on the external editor icon. This preference sets which command line will be used to launch the external editor. The parameter "$target"will be replaced in the command with the file name corresponding to the class, "$line" with the line number if this information is relevant, with 1 otherwise.
Internet browser (GTK platforms only) This sets the command line that should be used to open an internet browser on a given HTML page. If present, "$url" will be replaced with the URL of the HTML page. This is used to display help files.