A story that only ran in the test runner
A Storybook story imported a test-runner module, so the dev catalog could not render it while the test runner passed it, and the fix removed the story along with its import.
Two Storybook stories for reusable components checked a 320-pixel layout, and both imported a test-runner module to resize the viewport. That import resolves only under the Storybook test runner. The stories passed under the test runner, but the dev Storybook failed to render them, because a module that only works inside the test runner had been imported into a page that runs outside it.
Both stories sat in the catalog of reusable components, which is where the failure showed up in the dev server.
The fix removed the 320-pixel story from each file, along with its import. The browser tests already covered the keyboard at this width on the daily page, so the story’s play function repeated them. Layout checks like this need a real browser: component tests run in a DOM with no layout, so scroll and client width carry no meaning there, and only a browser can answer an overflow question.
Before the change, the dev catalog failed to render the keyboard story. After it, the keyboard and the duel word panel both rendered with no errors.