Soap / attribute questions

[stan92]

Hi,
I m very new to zimbra and its webservice.
I don't have any problem to consume it but I don't find the documentation about some attributes.
Here's an example when I retrieve all the folders.
I don't have no clue about the different attributes meanings like rev, i4next, i4ms, etc....

Any help ?
Stan

      <folder id="1" rev="1" i4next="2" s="0" i4ms="1" ms="1" name="USER_ROOT" n="0" l="11">
        <folder id="16" rev="1" i4next="17" s="0" i4ms="1" ms="1" name="Briefcase" n="0" l="1" view="document" />
        <folder f="#" id="10" rev="1" i4next="434" s="0" i4ms="1342" ms="1" name="Calendar" n="2" l="1" view="appointment" />
        <folder id="14" rev="1" i4next="15" s="0" i4ms="1" ms="1" name="Chats" n="0" l="1" view="message" />
        <folder id="7" rev="1" i4next="8" s="0" i4ms="1" ms="1" name="Contacts" n="0" l="1" view="contact" />
        <folder id="6" rev="1" i4next="7" s="0" i4ms="1" ms="1" name="Drafts" n="0" l="1" view="message" />
        <folder id="13" rev="1" i4next="269" s="0" i4ms="111" ms="1" name="Emailed Contacts" n="2" l="1" view="contact" />
        <folder id="2" rev="1" i4next="430" s="4594" i4ms="1331" ms="1" name="Inbox" n="2" l="1" view="message" />
        <folder id="4" rev="1" i4next="5" s="0" i4ms="1" ms="1" name="Junk" n="0" l="1" view="message" />
        <folder id="12" rev="1" i4next="13" s="0" i4ms="1" ms="1" name="Notebook" n="0" l="1" view="wiki" />
        <folder id="5" rev="1" i4next="268" s="809" i4ms="112" ms="1" name="Sent" n="2" l="1" view="message" />
        <folder f="#" id="15" rev="1" i4next="436" s="0" i4ms="1356" ms="1" name="Tasks" n="1" l="1" view="task" />
        <folder id="3" rev="1" i4next="430" s="67426" i4ms="1331" ms="1" name="Trash" n="51" l="1" />
      </folder>