I'm looking for some software (for Linux) to look inside Soundfont 2 packages, change things, and then pack it up again. That's all I need, but I can't find anything, so I'd love some recommendations.
There are a couple of applications I've come across for editing Sound Font files (*.sf2) in Linux:
Both of these applications are licensed under GPLv3 and are free to use and allow you to create new Sound Font files, edit existing files (replacing or adding to them, or removing sounds from a Sound Font file).
Additionally, Polyphone is available for Windows and Mac OS X.
Here is a screenshot of Polyphone with a Sound Font file open, listing all of the available sounds in the file along with information on the currently selected sound and the quick equalisation settings for that selected sound: