Affected versions

• ESR 60.6.0
• Latest Nightly 67.0a1
• Firefox 66.0

Affected platforms

• Ubuntu 18.04 x64
• Windows 10 x64
• macOS 10.14

Steps to reproduce

1. Open Firefox in Safe Mode:

• hamburger menu -> Help -> Restart with Add-ons Dissabled -> Restart -> Start in Safe Mode
• Go to about:support and click on Restart with Add-ons Disabled -> Restart -> Start in Safe Mode

2. Go to about:url-classifier (copy-paste the link in the URL bar or go to about:about and open the page with middle click.

Expected result

• The page is successfully loaded.

Actual result

• The page is loaded, but all the fields are blank.

Regression range

• I am not sure if this is a regression, but I will try to find it as soon as possible.

Additional Notes:

• The issue is not reproducing if you write the link in the URL bar.
• Even after you refresh the page, the bug is still reproducing. The fields are populated only after a restart.
• Please look at the attached png.

Regression range

• First bad: 2017-06-16 (20170617100144)
• Last good: 2017-06-17 (20170618030207)
• Pushlog: https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=bb8eab3c3ac4147848c4c85d628ba72029978665&tochange=316014448e427486cce211217e2aee2f18ee3d69

2017 regression and a P3, too late for 67.