you should list what languages kompozer is compatible with, e.g.
XHTML (what versions?),
HTML (what versions?),
SQL (what kinds? pgsql? mysql? mssql? sybase? oracle? ibm db2? only SQL92 standard?),
.txt (such as robots.txt?)
or whatever appropriately fits in the list that kompozer recognizes.
you should also list what browser(s) its layout engine is compatible with, or whether it is "its own".
these are important features to discuss, because developers are going to want to know these things.