I have added an SSH credential to Jenkins.
Unfortunately, I have forgotten the SSH passphrase and would now like to obtain it from Jenkins\' credential archive, which is
First, you need to get the encrypted value which is conveniently placed in the value
attribute of the password field of that credentials item you are interested in. Navigate to the credentials item in Jenkins UI you, click Inspect Element on the password field, and copy its value
attribute (something like {AQAABAAAa6VBbyzg5AWMW2RnfaBaj46}
Then, go to JENKINS_URL/script
and execute println( hudson.util.Secret.decrypt("{AQAABAAAa6VBbyzg5AWMW2RnfaBaj46}") )
; decrypted password appears under the input field