I realize there's a Mod2 for backstab damage. This is not what I'm referring to. I'm looking at items like Immaculate Rubicite Breastplate that show a Backstab Dmg value as a stat. It doesn't display in the Webtools but if viewed in game it shows Backstab DMG: 25 with the default UI at least.
There's a handful of other items like this around Golden Leaf of Calamity for example that also have this value. Doesn't seem to do anything so I'm wondering if this is an display or other error or broken? My rogue's backstab damage seems to unchanged when wearing items of this type.