Actually every melee weapon has an attack/defense bonus, which is represented by a number from 0 to 6. You can check in-game by examining the weapon in your inventory, and even mod the values:
https://www.unrealworld.fi/wiki/index.php?title=Weapons
On the other hand, the accuracy parameter should be only for bows and crossbows, but it's hidden in-game and cannot be modded.
Ranged accuracy is in the struct this table was scraped from (modifiable via cheat engine). Bonus attack and defense were not described in the struct as far as I could see. Maybe someone else can spot it:
http://prntscr.com/q0rttkAlso, bows aren't exclusive to the ranged accuracy value, spears also have a ranged accuracy (not described on wiki as far as i know).
http://prntscr.com/q0s2heedit: Potentially found attack/defence bonus. confirming atm.
Attack/defense bonus were stored in an unusual way making it hard to correlate the wiki values to data.
http://prntscr.com/q0saqb52 represents the attack AND defence bonus for the item staff in this case, converting 52 to hex we get 0x34, and then splitting the two numbers from each other we get the respective values 3 and 4 for defense and attack bonus. strange that its done this way...
here are some other values for reference:
Battlesword: Value 37, hex 0x25, bonus values 5 attack 2 defense.
Staff: value 52, hex 0x34, bonus values 4 attack, 3 defense.
Scimitar: value 34, hex 0x22, bonus values 2 attack 2 defense.
Boardsword: value 35, hex 0x23, bonus values 3 attack 2 defense.
Mace: value 19, hex 0x13, bonus values 3 attack 1 defense.
Highly likely this value represents the bonus'.
edit2: I have found another table created by someone on the wiki, including some values not included on this table. this is for version 3.52, however it should still be relevant.
https://github.com/fabio-t/UrwObjDump/blob/master/Dumps/3.52.constant.obj.csv