Affected versions

• Firefox 71.0b7
• Firefox 72.0a1
• Firefox 70.0.1
• Firefox 69.0
• Firefox 68.2.0esr

Affected platforms

• Windows 10 x64
• Windows 8.1 x64
• macOS 10.15
• Ubuntu 18.04 x64

Steps to reproduce

1. Launch Firefox with new profile.
2. Access the https://www.itisatrap.org/firefox/its-a-trap.html link.
3. Open Hamburger menu/Help.

Expected result

• "This isn't a deceptive site..." menu item is readable.

Actual result

• "This isn't a deceptive site" menu item is unreadable.

Regression range

• First bad: 2019.03.29
• Last good: 2019.03.28
• Pushlog: https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=3d678990e647da1ad1caa03c63c4736d09794274&tochange=d0c23055931239ae141171f8912bbefdfee06fbf
• Potential regressor: Bug 1523734

Additional notes

• Please observe the attached screenshot for further information regarding this issue.

The help view copies strings from the main menubar. When we moved the original DTD string
to ftl, there were performance implications for using it in browser.xhtml, so it was
only added once needed. The help view copies attributes from the items in the main menubar's
help menu, and so didn't copy the label for this item, resulting in the broken
behaviour.

To fix this, it's enough to have the string in the markup. As we've moved the other strings
into menubar.ftl, I'm taking the opportunity to move this string there, too, next to its
sibling string to report deceptive sites.

https://hg.mozilla.org/mozilla-central/rev/489afa3eb121

I can confirm this issue is fixed, I verified using Firefox 72.0a1 on Win 10 x64, macOS 10.15 and Ubuntu 18.04 x64.