Lintian
Lintian is a toolkit for linting Debian packages from the contents of the debian directory. Normally Lintian is just run from the extract source, and look for built files.
An example for the icingaweb2 package repository.
$ gbp buildpackage
$ lintian
N: Using profile debian/main.
N: Starting on group icingaweb2/2.7.3-2
N: Unpacking packages in group icingaweb2/2.7.3-2
N: Finished processing group icingaweb2/2.7.3-2
N: ----
N: Processing changes file icingaweb2
N: (version 2.7.3-2, arch source) ...
N: ----
N: Processing source package icingaweb2
N: (version 2.7.3-2, arch source) ...
N: ----
N: Processing buildinfo package icingaweb2
N: (version 2.7.3-2, arch source) ...
W: icingaweb2 source: changelog-should-mention-nmu
W: icingaweb2 source: source-nmu-has-incorrect-version-number 2.7.3-2
P: icingaweb2 source: package-uses-old-debhelper-compat-version 12
P: icingaweb2 source: rules-requires-root-missing
P: icingaweb2 source: source-contains-prebuilt-javascript-object public/js/vendor/jquery-3.4.1.min.js
P: icingaweb2 source: source-contains-prebuilt-javascript-object public/js/vendor/jquery-migrate-3.1.0.min.js
P: icingaweb2 source: source-contains-prebuilt-javascript-object public/js/vendor/jquery.sparkline.min.js
N: 1 tag overridden (1 info)
For more details and explanations, see the full output:
$ lintian --info --display-level pedantic --verbose