While working on
https://www.drupal.org/node/2858879
I looked at the error logs and at Drupals shiny new feature of showing css lint error along with phpunit errors.
one error log is
https://www.drupal.org/pift-ci-job/623708
A feature of the changes in the issue is that it touches just about all drupal-offcanvas related css files.
and so can be regarded as a accidental lint check
The error logs has "516 coding standards messages"
the bulk of them can be wiped away if we convert the #drupal-offcanvas id selectors into a .drupal-offcanvas class selectors.
This issue should only be started after the parent is complete.