encoded form. sv_utf8_downgrade(sv) does the opposite (if possible).
sv_utf8_encode(sv) is like sv_utf8_upgrade but the UTF8 flag does not
get turned on. sv_utf8_decode() does the opposite of sv_utf8_encode().
+Note that none of these are to be used as general purpose encoding/decoding
+interfaces: use Encode for that. sv_utf8_upgrade() is affected by the
+encoding pragma, but sv_utf8_downgrade() is not (since the encoding
+pragma is designed to be a one-way street).
=item *