LB83 is the DOS equivalent of LABN (83 stemming from the well known DOS 8.3 filename format - max 8 chars for filename and 3 for extension), although it is used in both The Dig and CMI for voice and music. I.e., it is a bundle of files.

"LB83"	dword	Block identifier
dwNamesOffs	dword	Byte offset to filenames (BE).
nFiles	dword	Number of files (BE)
szCompileDate	string	Compilation time and date.
??Unknown	?	Unknown stuff until first file.
at offset dwNamesOffs:
loop nFiles
sFileName	8 * char	First 8 characters. Characters not used are set to 00.
sFileExt	4 * char	The 3 characters of the extension. Characters not used are set to 00. Null-terminated.
dwOffset	dword	Byte offset to file relative to start of bundle (BE).
dwSize	dword	Size of file in bytes (BE).
end of loop