How do you see keystone information while spectating?

So after seeing the bond of stone changes I tried testing out support ...as you would expect the early and mid game were pretty bad and I only healed around 700 total hp....but after I bought apparently my total healing from that mastery jumped to a wopping 4,000 in the next group fight which, was also the last we won 4v5 after our adc got caught out and proceeded to kill nexus

The after game scoreboard .....under healing done said I only healed about 1.5k less then the enemy who had an

But while watching the replay I was unable to see the keystone so I am unsure how much it jumped and how much I was healing at what time all I know is that it seemed like my teammates took no damage.

Imagine this on amumu or singed...constant slow proc