Link to the GitHub repo:
https://github.com/torvalds/linux/blob/master/net/core/drop_...
I've recently made it on-by-default in NixOS and also collected some info about which other distros already have it on-by-default and since when: https://github.com/NixOS/nixpkgs/pull/85119
dropwatch is very useful, I used it to debug interruptions of our VPN setup between servers.