This task is what needs to be done before lubuntu-update-notifier is uploaded to the Ubuntu archive.

Here is a full breakdown of running Lintian with the -EvIL +pedantic flags. Before calling a package ready to upload, I always do a check with these flags. You can specify them in your ~/.sbuildrc like this:

$run_lintian = 1;
$lintian_opts = ['-EvIL', '+pedantic'];

Here is the annotated output, where E is error, W is warning, I is info, and P is pedantic:

W: lubuntu-update-notifier source: diff-contains-git-control-dir .git
P: lubuntu-update-notifier source: source-contains-empty-directory .git/branches/
P: lubuntu-update-notifier source: source-contains-empty-directory .git/objects/info/
P: lubuntu-update-notifier source: source-contains-empty-directory .git/refs/tags/

This is interesting; I've never seen this before. Here's the Lintian info page on it. Check it out, and try to address it.

P: lubuntu-update-notifier source: file-contains-trailing-whitespace debian/control (line 20)

Please fix this. Running wrap-and-sort probably fixes this too.

P: lubuntu-update-notifier source: package-uses-old-debhelper-compat-version 10
I: lubuntu-update-notifier source: out-of-date-standards-version 4.0.0 (released 2017-05-28) (current is 4.3.0)

Please bump your debhelper compat to 12 and your Standards-version to 4.3.0. You can bump the debhelper compat by editing debian/compat and editing the debhelper dependency in debian/control. You can bump Standards-version simply by editing debian/control.

W: lubuntu-update-notifier source: missing-debian-source-format

Please put 3.0 (native) in debian/source/format.

P: lubuntu-update-notifier source: no-dep5-copyright
E: lubuntu-update-notifier: copyright-file-contains-full-gpl-license
E: lubuntu-update-notifier: copyright-should-refer-to-common-license-file-for-gpl

Probably the most fun part here. The full GPL text must go into COPYING one directory up, and the debian/copyright file must follow DEP-5. There is an example copyright file in the DEP-5 specification, and here is an example of one I would also consider to be sane. Hands-down, the copyright file is probably the hardest part of packaging, and I don't blame you one bit for misstepping here. :)

I: lubuntu-update-notifier source: testsuite-autopkgtest-missing

As a wishlist item, perhaps consider writing some tests for the package. You can safely ignore this for now (override it if you wish).

W: lubuntu-update-notifier: wrong-bug-number-in-closes l3:#XXXXXX

Please file a wishlist bug against Ubuntu in Launchpad, and replace Closes: #XXXXXX with LP: #BUG_REF in the changelog.

I: lubuntu-update-notifier: extended-description-is-probably-too-short

Use your discretion on this one.

W: lubuntu-update-notifier: spelling-error-in-description allows to allows one to

Please fix this.

W: lubuntu-update-notifier: script-with-language-extension usr/bin/upgrader.py

Please fix this and re-test.

W: lubuntu-update-notifier: binary-without-manpage usr/bin/upgrader.py

Please fix this. You have some documentation already written when using -h, but please also put that in a manpage.

Please also consider removing the commented-out entries in debian/lubuntu-update-notifier.install and debian/rules.

Great work thus far! Let me know if you have any questions, and I look forward to being able to upload this.