Seen on a vendor patch bumping monolog...
https://gerrit.wikimedia.org/r/c/mediawiki/vendor/+/579666/
https://integration.wikimedia.org/ci/job/wmf-quibble-selenium-php72-docker/63166/console
22:00:40 [chrome 73.0.3683.75 Linux #0-6] Spec: /workspace/src/extensions/Wikibase/view/lib/wikibase-termbox/tests/selenium/specs/editing.spec.js
22:00:40 [chrome 73.0.3683.75 Linux #0-6] Running: chrome (v73.0.3683.75) on Linux
22:00:40 [chrome 73.0.3683.75 Linux #0-6] Session ID: 91a1c5b49548168ed6dc4e6196b81c96
22:00:40 [chrome 73.0.3683.75 Linux #0-6]
22:00:40 [chrome 73.0.3683.75 Linux #0-6] Termbox: editing
22:00:40 [chrome 73.0.3683.75 Linux #0-6] edit mode
22:00:40 [chrome 73.0.3683.75 Linux #0-6] ✓ is in edit mode after clicking the edit button
22:00:40 [chrome 73.0.3683.75 Linux #0-6] ✓ switches back to reading mode when clicking the cancel button
22:00:40 [chrome 73.0.3683.75 Linux #0-6]
22:00:40 [chrome 73.0.3683.75 Linux #0-6] editing
22:00:40 [chrome 73.0.3683.75 Linux #0-6] ✖ can edit labels, descriptions, and aliases
22:00:40 [chrome 73.0.3683.75 Linux #0-6] ✓ shows an error banner when an edit fails to save when the entity was protected while editing
22:00:40 [chrome 73.0.3683.75 Linux #0-6]
22:00:40 [chrome 73.0.3683.75 Linux #0-6] 3 passing (29.4s)
22:00:40 [chrome 73.0.3683.75 Linux #0-6] 1 failing
22:00:40 [chrome 73.0.3683.75 Linux #0-6]
22:00:40 [chrome 73.0.3683.75 Linux #0-6] 1) editing can edit labels, descriptions, and aliases
22:00:40 [chrome 73.0.3683.75 Linux #0-6] element (".wb-ui-event-emitting-button--edit") still not existing after 3000ms
22:00:40 [chrome 73.0.3683.75 Linux #0-6] Error: element (".wb-ui-event-emitting-button--edit") still not existing after 3000ms
22:00:40 [chrome 73.0.3683.75 Linux #0-6] at TermboxPage.waitUntilSaved (/workspace/src/extensions/Wikibase/view/lib/wikibase-termbox/tests/selenium/pageobjects/Termbox.page.js:117:19)
22:00:40 [chrome 73.0.3683.75 Linux #0-6] at Context.it (/workspace/src/extensions/Wikibase/view/lib/wikibase-termbox/tests/selenium/specs/editing.spec.js:48:16)