Modding - things that don't seem to be in the mod folder

Hello, I'm always tinkering around with things and I noticed that when it comes to the localisation descriptor for somethings, in particular the stark catacombs, don't show up in any localisation files in the mod folder at all.

The catacombs' entry in the castles.txt file located in the mod\A Game of Thrones\common\buildings directory says the following:


# Catacombs

ca_cellar_2 = {

desc = fp_cellar_2_desc

potential = {

FROMFROM = { title = b_winterfell }

}

gold_cost = 200

build_time = 365

ai_creation_factor = 78



#upgrades_from = ca_cellar_1



fort_level = 0.25

knights = 50

light_cavalry = -50



#martial = 1

#monthly_character_prestige = 0.25



extra_tech_building_start = 10.0 # Never get at start of game

}

______________________________________________
Now my question comes from the fact that the only file in the localisation folder that has any hint about this descriptor called fp_cellar_2_desc
shows up in 00_vanilla overrides and what it shows is actually fp_cellar_1_desc which is the descriptor for the normal wine cellar you can find in the arbor for example.

I tried checking the localisation folder in the original game but nothing shows up, and I myself have never seen such a building in the original name. At this point I am supposing that the descriptor I'm looking for is in one of the dlc .rar files? I sincerely doubt it but I don't see any other explanation other than that maybe this is a hard coded thing? but if that last idea is the right one, why would such a descriptor be hard coded into the mod?

Thank you in advance