I just discovered that iRacing support has been added and so far it has been excellent! I mostly drive in Rallycross races, which has much less support, however. Rallycross is also a feature in Project CARS 2 so I assume the following discussion could be applied that game as well.

For rallycross racing, once per race each driver is required to take a Joker lap. In American GRC, this is usually a shortcut across the track.
iRacing denotes Joker laps with an exclamation point after the time, and a blue crown symbol next to the name if that driver has taken their Joker.

The following are things I think deserve some attention, in order of priority.

BUG: Crew Chief reports the fastest Joker lap as the fastest lap of the race. Technically this is true, but in the case of Iowa Speedway the Joker cuts nearly 10 seconds off of my lap time. It's not helpful when Jim calls out "You're 8 seconds off the pace" when I put in my fastest regular lap time.

REQUEST: Keep track of my fastest Joker lap time. Similar to how time is reported by sector, It would be helpful to know my relative through a Joker during a practice session.

REQUEST: Notify me when other drivers take their Joker laps. I imagine this working in the same way I get notified if someone goes off track or pits. It is also useful to know if drivers around me have or haven't Jokered already so I can plan to Joker myself.

REQUEST: Remind me to Joker. This one is less critical, but if it's a white flag and I haven't Jokered yet, I'd hate to finish the race forgetting to do it. Especially when I get slapped with a penalty.

I use Crew Chief every time I race and it adds so much to my racing experience. Thank you!