Comment 6 for bug 217107

It does include Unicode characters, but you're right: Not as many as Dejavu. I don't know if it covers major European and Asian languages. The only page I found was this one: http://www.fileformat.info/info/unicode/font/liberation_sans/blocklist.htm

Of course Dejavu is the winner considering Unicode support, but what about hinting and other stuff? Changing the default font to Liberation Sans would fix some display errors. If a web developer writes "sans-serif" his designs will only look broken on linux, because Mac and Windows don't use fonts with a width like Dejavu Sans.

As you said, if a character is missing in Liberation Sans, one of Dejavu or any other font will be used. So why does the lack of some Unicode characters stop Liberation from being the default font?