The UCSC Genome Browser is developed and maintained by the Genome Bioinformatics Group at the University of California Santa Cruz. The website contains a large number of reference sequences and genome assemblies from different species. Sequences and annotation sets can be downloaded or viewed in the Genome Browser.
VCF The VCF format specification is available here. VCF (Variant Call Format) is a text file format (most likely stored in a compressed (for example gzipped) form). It contains meta-information lines, a header line and data lines containing information about a position in the genome.