LWG3094 [time.duration.io]p4 makes surprising claims about encoding

Author: jensmaurer

source/utilities.tex

@@ -19514,9 +19514,10 @@
 which are converted to arrays of \tcode{charT} using a decimal conversion with no leading zeroes.
 
 \pnum
-For streams where \tcode{charT} has an 8-bit representation,
-\tcode{"\textmu{}s"} should be encoded as UTF-8. Otherwise UTF-16 or UTF-32 is encouraged.
-The implementation may substitute other encodings, including \tcode{"us"}.
+If \tcode{Period::type} is \tcode{micro},
+but the character U+00B5 cannot be represented in
+the encoding used for \tcode{charT},
+the unit suffix \tcode{"us"} is used instead of \tcode{"\textmu{}s"}.
 
 \pnum
 \returns \tcode{os}.