ALERT ALERT, SPOILERS AHEAD!
You might've caught word of Tuesday's update for PCs accidentally being a development build, before they caught it and was able to release the correct version. Some users were able to run the incorrect version and found a whole bunch of interesting cars and content. For instance, what is believed to be the complete list of cars for a future Porsche expansion (although at least I was expecting there to be a Porsche expansion similar to FH2 and FM6). Looks like several other future DLC cars were also in that build.
If you want to know more, see for instance coverage by Kotaku and IGN, where some of the possible DLC cars are listed.
Since this post came with a spoiler alert, here's a spoiler for good measure:
(Photo by Lummi Photography: https://flic.kr/p/rFGxF4)