Example failure log: https://integration.wikimedia.org/ci/job/mwext-MobileFrontend-npm-run-lint-modules-docker/734/console
It seems like some files changed in mediawiki core and as such the linter is confused about mw.msg, which it finds defined in resources/src/mediawiki/mediawiki.base.js but that is not included in the default files list of the linter.