All reports of debian-control-file-uses-obsolete-national-encoding for the archive. The extended description of this tag is:
The Debian control file should be valid UTF-8, an encoding of the Unicode character set.
There are many ways to convert a control from an obsoleted encoding like ISO-8859-1; you may for example use "iconv" like this:$ iconv -f ISO-8859-1 -t UTF-8 control > control.new $ mv control.new control
Refer to Debian Policy Manual section 5.1 (Syntax of control files) for details.
This tag has not been emitted in any package tested by Lintian.