Normally, when you diff an [Ansible vault][], all you see is gibberish.
$ git diff -- group_vars/all/vault.yml
diff --git a/group_vars/all/vault.yml b/group_vars/all/vault.yml
index 245ccf4..90bf9ee 100644
--- a/group_vars/all/vault.yml
+++ b/group_vars/all/vault.yml
@@ -1,111 +1,111 @@
$ANSIBLE_VAULT;1.1;AES256