Each for each metadata field, there's now an automatically maintained "$field-lastchanged" that gives the timestamp of the last change to that field.

Note that this is a nearly entirely free feature. The data was already
stored in the metadata log in an easily accessible way, and already was
parsed to a time when parsing the log. The generation of the metadata
fields may even be done lazily, although probably not entirely (the map
has to be evaulated to when queried).

doc/todo/wishlist:_metadata_metadata_view.mdwn

@@ -18,3 +18,6 @@ Something along the lines of
 This would allow me to review files that haven't had any tag changes applied for a while and thus, may need the tags updating.
 
 I've done this in every tagging system I've used by (ab)using mtime, but that requires an additional step (of touching the file).
+
+> [[done]]; "$field-lastchanged" is automatically made available for each
+> field! --[[Joey]]