.uti files are the files that dictate the properties of items. Extracted or viewed in KotOR Tool, they have four tabs - General, Properties, Description and Comment. Some aspects of uti files are either not used, or not widely used in KotOR, being a leftover from NeverWinter Nights.
The General tab includes the various basic characteristics of the item - for example its name, its base item type, and its price.
Template ResRef - A string of text that matches an item's name.
Tag - Matches the Template ResRef.
Base Item - Defines the type of an item.
Cost - How much the item can be bought and sold for.
Additional Cost -
Palette ID - The ID for the item as defined in a file under the 'Palette File' branch of KotOR Tool.
Upgrade Level -
Charges - The number of uses a Droid weapon has before it's just a hunk of metal.
Stack Size - Believed to be the amount of an item in the inventory (for example medpack stacks)
Model Variation - Defines what model will be used.
Body Variation - Unknown, possibly used for the cut Phenotype defined in the .utc file.
Texture Variation - Defines what texture will be appiled when using an item.
The Properties tab includes the characteristics specific to that item, for example damage, alignment restrictions, and attribute bonuses. To add an item propterty, double-click the blank row and then start with the upper left dropdown list and fill in any others that turn white after you select an option for the first dropdown menu. Note that some of these have no effect, as they are left over from NeverWinter Nights.
The Description tab is the name(which appears in the inventory and equip screens) and item description that actually appears to the player in-game. The section for 'unidentified' is unused, as far as can be determined at this time. It is presumed to be a leftover from the Neverwinter Nights series.
The Comments tab is used purely so other developers/modders could differentiate between that and another version of a similar item, for example different coloured lightsaber crystals - it is usually left blank.