Regression: 8.x-1.8 release removes container_class attr entirely, causing front-end regressions for sites using feature

Problem/motivation

SA-CONTRIB-2026-209 was just released, as the container_class behavior was not sufficiently sanitizing user input. But the solution was to remove the feature entirely. This causes a regression, in some cases significant, for sites that utilize this feature.

Steps to reproduce

  1. Upgrade module to ^1.8
  2. Run drush updb and drush config:export
  3. See the container_class removed from menu_link_attributes.config.yml

Proposed resolution

  • @todo

Remaining tasks

  • TKTK