Default (control)
Open a photograph detail page with chrome forced off
Where: http://uxbri.local:5757/photos/2010/5008727893/?photo_chrome=control
Confirm Open full-size image is not visible
Where: same page - image, title, caption and credit remain; clicking the image still opens the largest JPEG; Previous / All / Next are absent
Treatment (chrome on)
Force the chrome arm
Where: http://uxbri.local:5757/photos/2010/5008727893/?photo_chrome=chrome
Confirm Open full-size image appears and the pager does not
Where: under the photograph actions on the same detail page - no Previous / All photographs / Next
Lab and kill switch
Find the rollout card on Lab
Where: http://uxbri.local:5757/lab/ - card "Photograph detail chrome"
Force control with the kill-switch query
Where: http://uxbri.local:5757/photos/2010/5008727893/?photo_chrome=control
Before promoting
Register photo_detail_chrome in GA4 Admin (user + event scoped) if measuring
Where: https://analytics.google.com/ -> Admin -> Custom definitions
When ready, change projects.yml phase / percentage and the JS phase constants
Where: _data/projects.yml id photo-detail-chrome and scripts/modules/photoDetailChrome.js