Below is from a Professor's answer.
It is straightforward to check this. west0479 resides in the demos folder where all such samples are kept.
>> which west0479.mat
We can get a list of the .mat files in this folder which might contain sparse matrices.
>> files = dir(fullfile(matlabroot,'toolbox','matlab','demos','*.mat'))
41×1 struct array with fields:
Each of these files can be loaded and checked for sparse variables. Let's make an array from these checks and use it to index the list of files, so only files containing sparse matrices are returned:
>> files(arrayfun(@(f) any(structfun(@issparse,load(fullfile(f.folder,f.name)))),files))
struct with fields:
folder: 'C:\Program Files\MATLAB\R2019b\toolbox\matlab\demos'
date: '14-Mar-2004 15:32:24'
west0479.mat is the only one.