这个XML是什么意思呢？

fnoctis

CraftingPiece的子节点PieceUsages无效？

PS:所有自己下载的MOD都出现这个问题，是游戏版本的问题吗？
new_pieces.xml代码如下：（红色行为报错行）
<?xml version="1.0" encoding="utf-8"?>
<CraftingPieces>
  <CraftingPiece id="tiandaowoba" name="天刀握把" tier="5" piece_type="Handle" mesh="tiandaowoba" length="40.19" weight="0.01" excluded_item_usage_features="long" item_holster_pos_shift="0,0,0.3" >
    <PieceUsages unavailable_usages="TwoHandedPolearm_Couchable:Javelin" />
    <BuildData piece_offset="0" next_piece_offset="20" previous_piece_offset="0" />
    <Materials>
      <Material id="wood" count="3" />
    </Materials>
  </CraftingPiece>
  <CraftingPiece id="tiandaowei" name="天刀尾" tier="5" piece_type="Pommel" mesh="tiandaowei" culture="Culture.empire" length="52" weight="0.1">
    <PieceUsages unavailable_usages="" />
    <BuildData piece_offset="0" next_piece_offset="30" previous_piece_offset="0" />
    <Materials>
      <Material id="Iron4" count="2" />
    </Materials>
  </CraftingPiece>
  <CraftingPiece id="tiandaoren" name="天刀刃" tier="5" piece_type="Blade" mesh="tiandaoren" length="96" weight="0.01">
    <PieceUsages unavailable_usages="" />
        <BuildData piece_offset="0" next_piece_offset="0" previous_piece_offset="10" />
    <BladeData stack_amount="10" physics_material="metal_weapon" body_name="bo_spear_b">
      <Swing damage_type="Cut" damage_factor="10" />
      <Thrust damage_type="Pierce" damage_factor="8" />
    </BladeData>
    <Materials>
      <Material id="Iron5" count="2" />
    </Materials>
  </CraftingPiece>
  <CraftingPiece id="tiandaohushou" name="天刀护手" tier="5" piece_type="Guard" mesh="tiandaohushou" culture="Culture.empire" length="35" weight="0.1">
    <PieceUsages unavailable_usages="" />
        <BuildData piece_offset="0" previous_piece_offset="0" />
    <Materials>
      <Material id="Iron4" count="2" />
    </Materials>
  </CraftingPiece>
</CraftingPieces>