This home improvement product company web page about an anti-mold product called Concrobium https://www.concrobium.com/products/mold-control-spray/ has the following table:
Ingredient Cas # Function
Water 7732-18-5 Solvent
Sodium Carbonate 497-19-8 Active Ingredient
Trisodium Phosphate 7601-54-9 Builder
Alkali Metal Carbonate Withheld Builder
Google says the alkali metal carbonates are Li2CO3, Na2CO3i and K2CO3 but returns nothing useful about other terms.
What do the parts not in plain English mean: "Cas #", "Builder", and "Withheld"?