TK-8252 .lvl files are what most of the files are made up of in SWB =/ (they are kind of like yes .pk3, .rfa etc.. compressed data, with directories/files etc..)
Im sure any hex editor would do though, nothing special, but please be careful.
Theres two pretty decent hex editors, please make sure to backup the file your editing
though... incase you save or mess something up
Someone who knows what they are doing and are proficient in code can write a decompressor/extrator for this eventually, and down the road a way to make .lvl files. Well see :x