> Few years ago it was built on top of Debian.
I don't think it's ever had anything to do with Debian? It was RHEL-like/RHEL-compatible (and now Fedora) AFAIK
https://readwrite.com/amazons-linux-ami-is-all-grown/
https://serverfault.com/questions/798427/what-linux-distribu...
https://en.wikipedia.org/wiki/Amazon_Machine_Image#Amazon_Li...
Are you sure of that? I thought Amazon Linux was always red hat based (mostly because of yum usage).
More here: https://serverfault.com/questions/798427/what-linux-distribu...
Few years ago it was built on top of Debian.