Comment 2 for bug 1844055

Some more context:

"New" keys.openpgp.org key server:
  https://keys.openpgp.org/about/news#2019-06-12-launch

Isses with SKS keyservers:
  https://medium.com/@mdrahony/are-sks-keyservers-safe-do-we-need-them-7056b495101c

OpenPGP certificate (key signature) flooding / spam:
  https://www.vice.com/en_us/article/8xzj45/someone-is-spamming-and-breaking-a-core-component-of-pgps-ecosystem
  https://gist.github.com/rjhansen/67ab921ffb4084c865b3618d6955275f
  https://dkg.fifthhorseman.net/blog/openpgp-certificate-flooding.html
  https://nvd.nist.gov/vuln/detail/CVE-2019-13050