app executable
man pages
known/found config files (eg kde rc files, /etc/, /usr/local/etc)
folders in home dir?

later:
if app is running, known network connections?
files referenced in man pages

use desktop files where possible
create and cache desktop files?

for kde apps:

apps - Applications menu (.desktop files). 
config - Configuration files. 
data - Where applications store data. 
exe - Executables in $prefix/bin. findExe() for a function that takes $PATH into account. 
mime - Mime types. 
tmp - Temporary files (specific for both current host and current user) 
socket - UNIX Sockets (specific for both current host and current user)

use

#include <kservice.h>
#include <kservicegroup.h>

		KService::Ptr service = KService::serviceByDesktopName( url.fileName() );
		if (service && service->isValid()) {
//			KURL newUrl;
//			newUrl.setPath(locate("apps", service->desktopEntryPath()));
//			createFileEntry(entry, service->name(), newUrl, "application/x-desktop", service->icon());

			createFileEntry(entry, service->name(), url.url(1)+service->desktopEntryName(),
                            "application/x-desktop", service->icon(), locate("apps", service->desktopEntryPath()) );