Affected versions

• 88.0b3, 89.0a1(2021-03-28), 87.0;

Affected platforms

• Windows 10, Ubuntu 20;

Steps to reproduce

1. Launch FIrefox, access about:url-classifier
2. Resize the browser to take up half of the screen

Expected result / Enhancement suggestion

• button centered inside the cell;

Actual result

• button set with a margin to left, not centered inside the cell;

Regression range

• will check when time permits it;
• traced back some old reports, bug 1535307 shows in the report issue being there(bug from 2 years ago so it's not something new);

Additional notes

• attached screenshot to illustrate the issue;
• while at it, the Last Update Status and Back-off time results might benefit from being centered as well as they're singular keywords.

This is not a regression, the issue reproduces all the way back to 66.0a1, so seems this is intended.