Durability is the adjustment of item effects, bonuses, etc. Most weapons, equipment, and other are in the lowest durability, 100 / 100.
Some weapon durability information and stats are not accurate, but considered different statistics of different adjustments. For example, some weapon articles in the wiki contain probably a durability of 116%, not 100, to have a stat or effect high enough. All weapons are required to be at 100, which is easy to correct.