> I don't know what Cold Harbor means in a Meta context

Cold Harbor is a reference to the TV show Severance.

Without going into any real spoilers it was the code name of a data classification project so mysterious that the people working on it weren't allowed to know what they were working on (and yes, the project in the show was probably named after the battle in the Civil War).

The Meta connection is that there are some humorous parallels between that project and a project involving people tagging data to train technology to replace themselves, and just the overall creepy dystopian vibe of both the fictional and real-world companies (and founders) involved.