Where is the .xsession file in linux mint?

I would like to know how I can use start up scripts in .xsession in order to change the look of my Desktop, I assumed .xsession was in my home directory so I performed at my home directory: ls -a to list all the hidden files, that start with a dot, but there was no .xsession file. So, I searched the whole file system beginning from the root with:

ls -Ra / | grep .xsession

but unfortunately it did not find this .xsession file either.