[RMMV] YANFLY ITEM UPGRADE SLOTS - UPGRADE ITEM ONLY WORKS ON A SPECIFIC ITEM NAME?

So in my game I'm using the Yanfly "Item Upgrade" plugin. This plugin allows you to use a new type of item to upgrade other types of items through a special menu. Each weapon/armor has a certain number of "upgrade slots" and to upgrade an item you must consume an "upgrade material" which will then be attached to one of the upgrade slots. Each upgrade material gives certain buffs and changes to the item it's equipped to, and you can select certain upgrades to only apply to certain types of weapons and armor, such as upgrade materials that only work on swords or other upgrade materials that only work on heavy armor.

If you're confused on what I'm talking about, information regarding the plugin can be found here: http://www.yanfly.moe/wiki/Item_Upgrade_Slots_(YEP)

Anyways, I have looked from the help documentation countless times and I cannot figure out what certain notetags that the plugin uses are supposed to mean. For example, this bit here:


I don't understand this part at all. Aren't the upgrades only supposed to be applied to weapons and armor? All these types only apply to regular items, not to weapons or armor. And then there is the issue with whatever "string" is. What is that even supposed to mean?


What does all this even mean? Type? What type? Because I just put the Upgrade Effect and select what weapon and armor types in the notetags and the upgrade items and everything works fine. Here is the notetag I use for a basic "power scroll":


Then for the actual weapons and armor I don't have to put in anything into the notetags and everything works fine. So what even is the purpose of this section of the help file? Because you can already change what type the upgrade item is in the database itself. And what the heck is string? None of this makes any sense to me.

All I want is a special upgrade item to only be applicable to one specific weapon. That's it. But there is no clear way to have special requirements for the upgrade items, just selecting what weapon or armor type you want to apply to it. I thought of making a new weapon type and having that weapon be both a sword and that new weapon type, but since I use Fallen Angel Olivia's "Weapon Switch System" all weapon types are available at all times in the menu so the menu will just spoil this special weapon type that's supposed to be hidden to the player and only used for behind the scenes stuff.

I thought that if the weapon upgrade system had a way to have more requirements for what items the upgrade item could apply to I could have the upgrade item to only be applicable to that one weapon by making the requirement the "name," but that seems impossible unless there's something I'm missing, especially with the string stuff. I looked up "what does string mean in JavaScript" and it said "basically just text lol" So I thought the string tag was a name requirement for a short bit, but that can't be it, can it? IDK but this plugin's help documentation is super confusing and completely unclear what notetags go with weapons and armor or items since they're all mixed together.

I did a bit of brainstorming while writing this post, and maybe the "types" mean that only upgrade items of a certain type can be applied to the weapon? And when you do "string" both the item and the weapon simply have to have matching text? I'll try that and see if it works, but I'm not 100% sure right now if that's what the help documentation really means. Because if it is it's worded in a super weird way that leaves me completely confused.