In the past one could add TBR=someone@chromium.org to the description and land the CL. Now there isn't R=someone@chromium.org line, so I've assumed that I shouldn't add TBR line either. It turned out that presubmit still requires it to be present, otherwise it fails: https://build.chromium.org/p/tryserver.infra/builders/Infra%20Presubmit/builds/2810.

I think presumit should check if I've +2'd CL myself and consider that TBR.