The tag is present in Lintian version 2.104.328. That is the most recent version we know about.
The file name in the patched source tree is not valid UTF-8. The file does not appear in the upstream files. Its appearance is considered the responsibility of the package maintainer. Please rename the file.
Unlike other file names in Lintian, which are printed in UTF-8, the attached reference shows the bytes used by the file system. Unprintable characters may have been replaced.
Please refer to Debian Policy Manual section 10.10 for details.