(For git stash basics have a look at Using the Stash.)
It’s possible to do a diff inside a stash entry:
$ git stash show stash@{0} -u
Shorthand for the latest stashed entry:
$ git stash show -u
To get a list of filenames in a stash entry:
$ git stash show stash@{0} --name-only
Get only a certain file from stash:
$ git checkout stash@{0} --
Rename file in stash entry:
$ git show stash@{0}: