here some more information about the tools contained in this package and how to use them.
In general if you are looking for something which does not depend on AiiDA and may not be FLEUR specific, the place to look for is the masci-tools repository and its documentation. This includes:
parsers for files
utility for xml
Tools and utility which does depend on AiiDA but is not FLEUR specific you find in the aiida-jutools repository
Meta AiiDA database analysis
Since so far we lack a in detail documentation of tools and utility within aiida-fleur you are referenced to the automatic documenation of tools and utility.