Format of KeysList record in release 3.02.06. It is never compressed. There is one KeysList record for the main (TFile) directory and one per non-empty subdirectory. It is probably not accessed by its key, but from its offset given in the directory data.
----------TKey---------------
byte 0->3 Nbytes = Number of bytes in compressed record (TKey+data) TKey::fNbytes
4->5 Version = TKey class version identifier TKey::fVersion
6->9 ObjLen = Number of bytes of uncompressed data TKey::fObjLen
10->13 Datime = Date and time when record was written to file TKey::fDatime
| (year-1995)<<26|month<<22|day<<17|hour<<12|minute<<6|second
14->15 KeyLen = Number of bytes in the key structure (TKey) TKey::fKeyLen
16->17 Cycle = Cycle of key TKey::fCycle
18->21 SeekKey = Byte offset of record itself (consistency check) TKey::fSeekKey
22->25 SeekPdir = Byte offset of parent directory record (directory) TKey::fSeekPdir
26->26 lname = Number of bytes in the class name (5 or 10) TKey::fClassName
27->.. ClassName = Object Class Name ("TFile" or "TDirectory") TKey::fClassName
0->0 lname = Number of bytes in the object name TNamed::fName
1->.. Name = lName bytes with the name of the object `<directory-name>` TNamed::fName
0->0 lTitle = Number of bytes in the object title TNamed::fTitle
1->.. Title = lTitle bytes with the title of the object `<directory-title>` TNamed::fTitle
----------DATA---------------
0->3 NKeys = Number of keys in list (i.e. records in directory (non-recursive))
| Excluded:: The directory itself, KeysList, StreamerInfo, and FreeSegments
4->.. TKey = Sequentially for each record in directory,
| the entire TKey portion of each record is replicated.
| Note that SeekKey locates the record.
