At 9th level, the Gloomblade archetype allows the following shadow effect, found under Shadow Weapon training; "During the gloomblade’s turn, he can increase his reach with that weapon by 5 feet." https://www.d20pfsrd.com/classes/core-classes/fighter/archetypes/paizo-figh ter-archetypes/gloomblade-fighter-archetype/
Does this merely mean that a gloomblade's reach increases for the sake of attacks during their turn, as per the Lunge feat? Or does this ability allow the gloom blade to effectively increase the extent of their threatened squares, using this ability to perform attacks of opportunity at 5 feet more than they would otherwise?