What "Yellow Magnesium" actually means
It is Google's internal label for a functionality violation: on the reviewer's machine the core feature didn't work, wasn't reachable, or wasn't substantial enough to justify being an extension.
The things that trigger it most:
- Doesn't work on a clean install — a console error, a missing backend, or a bug the reviewer hit immediately.
- Login / paywall wall — the feature is locked behind an account or payment the reviewer can't get past.
- Too thin — a simple redirect, a single bookmark, or a wrapper around a website with little added value.
- Region or site dependency — it only works on a site or region the reviewer couldn't reach.
How to fix it and resubmit
- Make it demoable without login. Provide a guest mode, a demo, or test credentials in the reviewer notes so the core feature is reachable.
- Ship zero console errors. Install fresh, open the console, and confirm the main flow runs clean before you resubmit.
- Show real value. If it's a thin wrapper, add functionality that genuinely helps — reviewers reject "could be a bookmark".
- Leave reviewer notes. Explain exactly how to trigger the feature and on which site, so a busy reviewer sees it work in seconds.
Rule of thumb: assume the reviewer spends 60 seconds and reads no docs. It must work, visibly, in that minute.
Yellow Magnesium is one of six rejection families (permissions/Purple Potassium, metadata/Blue Argon, single purpose, privacy, remote code, functionality). If your email lists more than one, fix them together — a second rejection resets the review clock.
Not sure why the reviewer couldn't run it?
Paste your rejection email — get the exact cause in seconds, free. Or we fix it and resubmit for you.
Free diagnosis → Single purpose rejection? →