As of September 2017, data (tarballs and binaries) for BioC versions 1.8-2.6
were moved off master.bioconductor.org to an S3 bucket that serves as a static
website. The S3 bucket, archive.bioconductor.org, contains only bin/ and src/
level directories.  Redirects to the S3 location from master.bioconductor.org
are in /extra/www/bioc/packages/.htaccess.

The goal is to move static data off master.bioconductor.org to make room for
future releases. Also, S3 is a much cheeper storage option than the EBS
back-end of an EC2 instance. Additional BioC releases will likely be moved off
master.bioconductor.org in 2018.