dd87117369624a1c9662d47db73146b78f98c2ca
max
  Fri Nov 17 07:47:02 2023 -0800
after discussion with Francoise at NCBI, adapting refseq track docs a little

diff --git src/hg/makeDb/trackDb/human/refSeqComposite.html src/hg/makeDb/trackDb/human/refSeqComposite.html
index bd71253..437ba58 100644
--- src/hg/makeDb/trackDb/human/refSeqComposite.html
+++ src/hg/makeDb/trackDb/human/refSeqComposite.html
@@ -29,31 +29,33 @@
           </strong></em></dt>
   <ul>
     <li>
     <em>RefSeq All</em> &ndash; all curated and predicted annotations provided by 
     RefSeq.</li>
     <li>
     <em>RefSeq Curated</em> &ndash; subset of <em>RefSeq All</em> that includes only those 
     annotations whose accessions begin with NM, NR,  NP or YP. <small>(NP and YP are used only for
     protein-coding genes on the mitochondrion; YP is used for human only.)</small></li>
     <li>
     <em>RefSeq Predicted</em> &ndash; subset of RefSeq All that includes those annotations whose 
     accessions begin with XM or XR.</li>
     <li>
     <em>RefSeq Other</em> &ndash; all other annotations produced by the RefSeq group that 
     do not fit the requirements for inclusion in the <em>RefSeq Curated</em> or the 
-    <em>RefSeq Predicted</em> tracks.</li>
+    <em>RefSeq Predicted</em> tracks, as they do not have a product and therefore no RefSeq accession.
+    More than 90% are pseudogenes, T-cell receptor or immunoglobulin segments.
+    The few remaining entries are gene clusters (e.g. protocadherin).</li>
     <li>
     <em>RefSeq Alignments</em> &ndash; alignments of RefSeq RNAs to the $organism genome provided
     by the RefSeq group, following the display conventions for
 <a href="../goldenPath/help/hgTracksHelp.html#PSLDisplay" target="_blank">PSL tracks</a>.</li>
    <li>
    <em>RefSeq Diffs</em> &ndash; alignment differences between the $organism reference genome(s) 
    and RefSeq transcripts. <small>(Track not currently available for every assembly.)</small>
    </li>
    <li>
     <em>UCSC RefSeq</em> &ndash; annotations generated from UCSC's realignment of RNAs with NM 
     and NR accessions to the $organism genome. This track was previously known as the &quot;RefSeq 
     Genes&quot; track.</li>
    <li>
    <em>RefSeq Select+MANE (subset)</em> &ndash; Subset of RefSeq Curated, transcripts marked as 
    RefSeq Select or MANE Select.