Rabi has been a core reviewer on Heat for more than 4 years, and is a
former PTL. In that time he's done hundreds of backports:

https://review.opendev.org/#/q/owner:ramishra%2540redhat.com+branch:%22%255Estable/.*%22+project:openstack/heat

(Only two of which we ended up deciding not to merge, the last of which
was in 2016.)

As well as a good number of reviews:

https://review.opendev.org/#/q/reviewedby:ramishra%2540redhat.com+branch:%22%255Estable/.*%22+project:openstack/heat+NOT+owner:%22Rabi+Mishra+%253Cramishra%2540redhat.com%253E%22

Rabi also maintains a downstream distribution of Heat, so he is fully
aware of the pain that backporting inappropriate changes can cause. He
is well aware of the stable branch guidelines and is, if anything, more
conservative than I am in applying them. I'm 100% confident he will not
be approving any feature backports.

I'll be spending some extended time away from a keyboard in the near
future, so it's important that we increase the bus factor (from 1) of
heat-stable-maint team members.

thanks,
Zane.