From Team Fortress Wiki

The following table describes the possible attributes of weapons and items as contained in the items_game.txt file. This is the list of item attributes as described to the user, so some attributes will be duplicated if they can both appear as positive or negative (such as a damage bonus/penalty) or if they have several different descriptions ("set_weapon_mode" is used to represent alternate versions of half a dozen different weapons).

This table lists:

ID : Internal ID reference of that attribute. Not used directly in this file, but mods may refer to this value.

: Internal ID reference of that attribute. Not used directly in this file, but mods may refer to this value. Name : Internal name of this attribute.

: Internal name of this attribute. Description : The text that appears for the user in the weapon's description. " %s1 " is replaced with the value of the attribute.

: The text that appears for the user in the weapon's description. " " is replaced with the value of the attribute. Value Type : How the value of this attribute is formatted for display. Possible types are additive (flat value), percentage, additive percentage (for percentages that start from 0% instead of 100%, like chance to slow target) and inverted percentage (a positive "mult_postfiredelay" will be translated to a negative fire rate percentage)

: How the value of this attribute is formatted for display. Possible types are additive (flat value), percentage, additive percentage (for percentages that start from 0% instead of 100%, like chance to slow target) and inverted percentage (a positive "mult_postfiredelay" will be translated to a negative fire rate percentage) Class: This is the attribute's name used by the rest of the items_game.txt document, as in when it defines each weapon's attributes.

List