In #15643 the github-merge.py script was updated so that merge commits would include review comments.
However, the script seems to be missing comments. i.e the recently merged #15557 includes:
ACKs for commit 184f87:
jnewbery:
utACK 184f8785f710d58d9ef82e611591c9cbff5ab89d
Tree-SHA512: fb6542bdfb2c6010e328ec475cf9dcbff4eb2b1a1b27f78010214534908987a5635797196fa05edddffcbcf2987335872dc644a99261886d5cbb34a8f262ad3e
Looking at the PR there should also be utACKs from ryanofsky and promag.