What specifically do you mean by "MATLAB library *.m files"?
If you mean the *.m files for built-in functions like matrix multiplication (the * operator or mtimes function), plot, etc. those built-in functions are not implemented as MATLAB code and we don't distribute the source code for those built-in functions.
If you're asking about the files that implement non-built-in functions that are included as part of MATLAB (like ode45.m), if you've installed MATLAB they are provided as part of the installation.
If you mean something else by that term, please clarify what you're looking for any how you hope to use that information if it is available.
