Currently that description is missing at branch_6x so I'd like to restore it.
User feedback: http://markmail.org/message/hxtxzue7qn6ne6vz
Here is a patch for branch_6x.
I carried over the content from branch_6_1 and updated segment info links and history as 62 codec.
Thank you Shinichiro Abe, this looks great, I'll push soon.
Commit 830a3fdfbf12553d47f8f6c320c862aa88fdc48b in lucene-solr's branch refs/heads/branch_6x from Mike McCandless
[ https://git-wip-us.apache.org/repos/asf?p=lucene-solr.git;h=830a3fd ]
LUCENE-7532: add back lost codec file format documentation
Thanks Shinichiro Abe!