This is probably not of much interest for normal users.
If you work with OpenDocument and OpenOffice.org, you know that XML file produced by OpenOffice.org is not quite human-friendly as it contains no CR/LF and no indentation because it is (so to speak) “optimized” for size. The XML file of course looks ugly in normal text editor. To change this, open menu Tools, Option to bring the Options dialog. Choose Load/Save, General from the list of the left and uncheck the option Size optimization for XML format.