Varnish Cache 6.6.0 released

We have rolled our usual biannual Varnish Cache release, this time 6.6.0:
Quite a lot of improvements and bugfixes this time, and a new, modular but 100% backwards compatible “builtin.vcl”, which we hope will make VCL writing even easier.
This release also marks that the Varnish Cache project is now 15 years old.
Thanks to everybody who made that possible!