Voicebanks for Utau (free (as in beer, iirc) clone of Vocaloid) are primarily distributed as SHIFT-JIS encoded zips. For example, try downloading Yufu Sekka's voicebank: http://sekkayufu.web.fc2.com/ . If I try to unzip the "full set" zip, it produces a folder called РсЙ╠ГЖГtТPУ╞Й╣ГtГЛГZГbГgБi111025Бj. But unar detects the encoding and properly extracts it as 雪歌ユフ単独音フルセット（111025). I'm sure there's some flag you can pass to unzip to specify the encoding, but I like having unar handle it for me automatically.