https://lucene.apache.org/lucene-parent/lucene-spatial-extras: Advanced Spatial Shape Strategies for Apache Lucene (The Apache Software Foundation) 
public class org.apache.lucene.spatial.prefix.NumberRangePrefixTreeStrategy$Facets$FacetParentVal
  minor version: 0
  major version: 59
  flags: flags: (0x0021) ACC_PUBLIC, ACC_SUPER
  this_class: org.apache.lucene.spatial.prefix.NumberRangePrefixTreeStrategy$Facets$FacetParentVal
  super_class: java.lang.Object
{
  public int parentLeaves;
    descriptor: I
    flags: (0x0001) ACC_PUBLIC

  public int childCountsLen;
    descriptor: I
    flags: (0x0001) ACC_PUBLIC

  public int[] childCounts;
    descriptor: [I
    flags: (0x0001) ACC_PUBLIC

  public void <init>();
    descriptor: ()V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // org.apache.lucene.spatial.prefix.NumberRangePrefixTreeStrategy$Facets$FacetParentVal this
         0: .line 175
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
            return
        end local 0 // org.apache.lucene.spatial.prefix.NumberRangePrefixTreeStrategy$Facets$FacetParentVal this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lorg/apache/lucene/spatial/prefix/NumberRangePrefixTreeStrategy$Facets$FacetParentVal;
}
SourceFile: "NumberRangePrefixTreeStrategy.java"
NestHost: org.apache.lucene.spatial.prefix.NumberRangePrefixTreeStrategy
InnerClasses:
  public Facets = org.apache.lucene.spatial.prefix.NumberRangePrefixTreeStrategy$Facets of org.apache.lucene.spatial.prefix.NumberRangePrefixTreeStrategy
  public FacetParentVal = org.apache.lucene.spatial.prefix.NumberRangePrefixTreeStrategy$Facets$FacetParentVal of org.apache.lucene.spatial.prefix.NumberRangePrefixTreeStrategy$Facets