Rehello @g-schick 
,
Thanks for the clarification about nesting in Calc.
I think it will be quite tricky because your selector on head of column “Folder 2” will not be filtered according to selected “Folder 1” unless you do some BASIC scripting in Calc. Neither impossible, nor simple enough in my opinion.
No. Because of the structure (folders, files) a simple script may do this job.
Ok, unfortunately some of the metadata is not in the structure of folders, files, like the amount of the invoice in my example. Even people organized like my mother use some Blob text after some level of complexity :). That’s where Natural Language Processing comes into play.
I think you posted this in the right place. But I’m no Linux developer. Your title caught my attention and reading your first post I started thinking of other possible solutions.
No problem :). Thanks for trying to help :). When I’ll have an answer on Linux Kernel mailing list, we will have more elements to judge.
Best regards,
Laurent Lyaudet