Check out the "cbb_display_group" tag which is already being set.

cbb_display_group shows 'Production Tryjob' or 'Tryjob', but I need 'pre_cq'.

If the new waterfall doesn't filter on build_type flag, I'll add build_type to all tryjobs (like https://cs.corp.google.com/chromeos_public/chromite/cbuildbot/stages/scheduler_stages.py?l=61) ? 

if the new waterfall does rely on the build_type flag, I'll only add build_type:pre_cq for all Pre-CQ builds.

So Production Tryjob = pre_cq in cbb_display_group ? 

I think it will be reasonable to rename "Producuction Tryjob" to "Pre CQ" or whatever friendly name you would prefer.

Re #6: I'll add build_type:pre_cq and will not touch cbb_display_group

Sure. Let us rename cbb_display_group to "Pre CQ" as well. Let's also decide on a list of names for other groups. I'll update go/cros-builds-group

Or you can hold off changing the cbb_display_group until we decide on the name format of the display group. 

I believe that CL:731827 will define teh pre_cq value, and it will be used after CL:731828.

fixed at https://chromium-review.googlesource.com/c/chromiumos/chromite/+/754292