Entry from TrinityCore source :
struct TaxiNodesEntry
{
    uint32 ID;                                                      // 0
    uint32 MapID;                                                   // 1
    DBCPosition3D Pos;                                              // 2-4
    LocalizedString* Name;                                          // 5
    uint32 MountCreatureID[2];                                      // 6-7
    uint32 ConditionID;                                             // 8
    uint32 LearnableIndex;                                          // 9 - some kind of index only for learnable nodes
    uint32 Flags;                                                   // 10
    DBCPosition2D MapOffset;                                        // 11-12
};
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My entry in map.xml :
   <TaxiNodes>
      <element>
		<name>ID</name>
		<type>uint32</type>
	 </element>
	 <element>
		<name>Map</name>
		<type>uint32</type>
	 </element>
	 <element>
		<name>PosX</name>
		<type>float</type>
	 </element>
	 <element>
		<name>PosY</name>
		<type>float</type>
	 </element>
	 <element>
		<name>PosZ</name>
		<type>float</type>
	 </element>
	 <element>
		<name>Name</name>
		<type>string</type>
	 </element>
	 <element>
		<name>MountCreatureID_1</name>
		<type>uint32</type>
	 </element>
	 <element>
		<name>MountCreatureID_2</name>
		<type>uint32</type>
	 </element>
	 <element>
		<name>ConditionID</name>
		<type>uint32</type>
	 </element>
	 <element>
		<name>LearnableIndex</name>
		<type>uint32</type>
	 </element>
	 <element>
		<name>Flags</name>
		<type>uint32</type>
	 </element>
	 <element>
		<name>MapOffsetX</name>
		<type>float</type>
	 </element>
	 <element>
		<name>MapOffsetY</name>
		<type>float</type>
	 </element>
   </TaxiNodes>