This seems to work in the Fixlet Debugger. Not sure when used in analsysis.
(concatenations of lines whose (it does not contain "xml version") of it) of (find files "*.xml" of descendant folders of folder "C:\Program Files (x86)\BigFix Enterprise\BES Client\__BESData")
(concatenations of lines whose (it as lowercase does not contain "xml version") of it) of descendants whose(name of it as lowercase = "info.xml") of folders "d:\_snapshots"
As @gearoid points out, the descendants and descendant folders inspectors are expensive and slow depending on the situation, so be careful. It is best to use them in an analysis property with a limited report time. (Once a day)