Reveal formatting

See the attached workbook. B1 is visually different from A1 and C1, but everything I've been able to reveal shows they're formatted the same. However, if copy and paste the formats one to another, you can see that they're different.

B1 comes from another report, and I want to reproduce the same style on a current report without having to copy/paste from the old report. So, how do I reveal what makes B1 different?

Thanks,
John