Comment 3 for bug 1925840

/usr/share/ecryptfs-utils/ecryptfs-record-passphrase appears to be a text file:

_Name: Record your encryption passphrase
Priority: High
OnlyAdminUsers: False
DisplayIf: test -e $HOME/.ecryptfs/wrapped-passphrase -a ! -e $HOME/.ecryptfs/.wrapped-passphrase.recorded
Terminal: True
GettextDomain: ecryptfs-utils
Command: "sh -c 'ecryptfs-unwrap-passphrase $HOME/.ecryptfs/wrapped-passphrase 2>/dev/null && echo [Enter] && head -n1 && touch $HOME/.ecryptfs/.wrapped-passphrase.recorded '"
_Description:
 To encrypt your home directory or "Private" folder, a strong
 passphrase has been automatically generated. Usually your directory is unlocked
 with your user password, but if you ever need to manually recover this
 directory, you will need this passphrase. Please print or write it down and
 store it in a safe location.
 If you click "Run this action now", enter your login password at the
 "Passphrase" prompt and you can display your randomly generated passphrase.
 Otherwise, you will need to run "ecryptfs-unwrap-passphrase" from the command
 line to retrieve and record your generated passphrase.

AFAIU update-manager is supposed to show the text from it, but instead it shows the (null).

I don't know exactly how ecryptfs communicates with update-notifier. Running strings on the pam_ecryptfs PAM module shows

    /var/lib/update-notifier/user.d/ecryptfs-record-passphrase
    /var/lib/update-notifier/dpkg-run-stamp

the first of those is a symlink to /usr/share/ecryptfs-utils/ecryptfs-record-passphrase, the second is a regular empty file.

I think pam_ecryptfs creates the symlink and touches the stamp file to wake up a sleeping update-notifier? Or maybe something more complicated, since I was trying to reproduce the bug with sudo touch /var/lib/update-notifier/dpkg-run-stamp and it did not work.