Now I can build git-annex twice as fast! And a typical incremental build is down to 10 seconds, from 51 seconds.
Spent a productive evening working with Guilhem to get his encryption patches reviewed and merged. Now there is a way to remove revoked gpg keys, and there is a new encryption scheme available that uses public key encryption by default rather than git-annex's usual approach. That's not for everyone, but it is a good option to have available.