lib/less/parser/parser.js
function () {
                var e, expressions = [], index = parserInput.i;

                do {
                    e = this.expression();
                    if (e) {
                        expressions.push(e);
                        if (!parserInput.$char(',')) { break; }
                    }
                } while (e);

                if (expressions.length > 0) {
                    return new(tree.Value)(expressions, index);
                }
            }
function () {
                var e, expressions = [], index = parserInput.i;

                do {
                    e = this.expression();
                    if (e) {
                        expressions.push(e);
                        if (!parserInput.$char(',')) { break; }
                    }
                } while (e);

                if (expressions.length > 0) {
                    return new(tree.Value)(expressions, index);
                }
            }
function ( ) { var e , expressions = [ ] , index = parserInput . i ; do { e = this . expression ( ) ; if ( e ) { expressions . push ( e ) ; if ( ! parserInput . $char ( ',' ) ) { break ; } } } while ( e ) ; if ( expressions . length > 0 ) { return new ( tree . Value ) ( expressions , index ) ; } }
A Value is a comma-delimited list of Expressions  font-family: Baskerville, Georgia, serif;  In a Rule, a Value represents everything after the `:`, and before the `;`.
A Value is a comma - delimited list of Expressions font - family : Baskerville Georgia serif ; In a Rule a Value represents everything after the : and before the ; .