Tails

The first time one is supposed to check Jenkins happens here:

1. <a id="reproducibility-sanity-check-iso"></a>
   Let's sanity check that Jenkins reproduced your images.

   Visit the URL printed by this command:

       echo "https://jenkins.tails.boum.org/job/build_Tails_ISO_${RELEASE_BRANCH}/"

   Find the job (probably the last one)
   and make sure the ISO and USB images built by Jenkins:

   - were built from the correct Git commit
   - have the same file size as the images you built
   - have the same hash (in the `.shasum` file) as the images you built

but one is only asked to set/remember the proper job ID later on, in:

Publish the ISO, IMG, and IUKs over HTTP
----------------------------------------
[…]
Pick a build from `$RELEASE_BRANCH` that produced identical ISO and USB images
to the ones you've built locally (`XXX` must be the job ID, i.e.
an integer):

    MATCHING_JENKINS_BUILD_ID=XXX

Maybe we could suggest setting the right variable the first time around?