chromium/tools/metrics/histograms/test_data/enums.xml

<histogram-configuration>

<!-- Enum types -->

<enums>

<enum name="Enum_A">
  <int value="0" label="Value0"/>
  <int value="1" label="Value1"/>
</enum>

<enum name="Enum_X">
  <int value="0" label="Value0"/>
  <int value="1" label="Value1"/>
</enum>

<enum name="UkmEventNameHash">
  <summary>
    Placeholder enum. The values are UKM event name hashes truncated to 31 bits.
    This gets populated by the GetEnumsNodes function in merge_xml.py when
    producing the merged XML file.
  </summary>
</enum>

</enums>

</histogram-configuration>