I want to develop some scripts for things like Chrx, Chromebrew, MrChromebox scripts etc and I don't want to register a new SSH key to my account every time I need to powerwash or use recovery on one of my Chromebooks because I messed it up. I already use my Yubikey for GPG/FIDO/U2F/SSH on all the other systems I develop on, and I only needed the SSH portion to work for this particular use case. I also didn't want to deal with using Crouton or Crostini since that requires additional downloads and more configuration and complexity.
Since the Crosh userland doesn't have scdaemon or pcscd for talking to the smart card, I had to come up with another way to access the Yubikey and make the SSH key available. I ended up trying a few different things to make it work, but overall the solution ended up being brilliantly straightforward. Originally I tried using Chromebrew to install one of the smartcard access/manager packages, but the dependency chain ended up pulling in Gnome keyring and a