Hi. This is a bug that results from a missing localization string in the language files. It applies to all languages at the moment. Neocore is aware of it, but hasn't pushed a fix yet. (I presume it's lower priority than, say, the missing stash items and crafting problems.)

There are actually two versions of it, a primary (bright light blue square, which can appear on TA weapons) and secondary (duller blue square, which can appear on Eye Implants, Neural Implants, Purity Seals, and Signums). Both should have a description of "X% melee damage bonus to constructs", and they differ only in how much damage they offer. It should work as expected.

Hope that helps!