Leftfield Style Overview
Leftfield Music Description
On Discogs, this term tends to be applied to anything with a "quirky" component, or anything that's atypical of its genre, or to which no other style really seems to apply.
Sometimes it is used as a less-alienating alternative for the term Experimental.
There is major potential for overuse of this tag, and as more styles are added, they can potentially be used to replace this tag where there was previously no better description.