I want to inspect a stash and find out what changes it would make if I applied it to working tree in its current state.
I know I can do a git diff on the stash, but this shows me all the differences between the working tree and the stash, whereas I'm just interested to know what the stash apply is going to change.
git stash show will show you the files that changed in your most recent stash. You can add the -p option to show the diff.
git stash show -p
If the stash you are interested in is not the most recent one, then add the name of the stash to the end of the command:
git stash show -p stash@{2}