-(defaults to "fg_log.csv"), an optional 'interval-ms' property
-(defaults to 0, which logs every frame), and a series of 'entry'
-subbranches.
+(defaults to "fg_log.csv"), an optional 'delimiter' property (defaults
+to a comma), an optional 'interval-ms' property (defaults to 0, which
+logs every frame), and a series of 'entry' subbranches. The
+'delimiter' property uses only the first character of the property
+value as the delimiter. Note that the logger does no escaping, so you
+must choose a delimiter that will not appear in the property values
+(that's not hard, since most of the values are numeric, but watch for
+commas in the titles).