Every field ID found in Mappings or Buildups file can be found here with the descriptions maintained in SAP.
In the following you can see an Example for the field 0MATERIAL of the Advanced DataStore Object ZDL_A19 and for the field BASE_UOM of Open Hub Destination ZPUROH01.
<node id="0MATERIAL|ZDL_A19|ADSO">
<description language="E" text="Material (ADSO spec)" />
</node>
<node id="BASE_UOM|ZPUROH01|DEST">
<description language="E" text="Base Unit of Measure" />
<description language="D" text="Basismengeneinheit" />
</node>