There are so many wise men on this forum.
I have recently spotted that many of my classical files have a [Grouping] tag set , but not by me and in too many files to be an accident (10 k out of 140k)
It tends to hold the Composition Name eg Symphony No 5 in C Minor Op.67, but in some cases is "Romantic" or some other descriptor of mode etc.
Has any body any idea where it comes from an how it's used ?