I don't think Comcast really publishes upload speeds anymore. Even their own speed test hides it.
It is over-provisioned the typical 20%. I have 100/5, but it tests 120/6. I think some of the Blast tiers offer 10. The highest upload speed is 35, which is only available with Gigabit.
I should mention Comcast does offer higher upload speeds, but that is only on certain business-class accounts in areas where they can run fiber to a location. Standard cable is limited due to current technical reasons.
