Can I get a warning about EOL of a kernel?

script written yesterday - use hook pacman

is not for EOL but same logic
Last paragraph tests if an installed kernel no longer exists (after EOL)
First, scrape websites

for eol, i have also a python script : test if kernel is not in testing or unstable. use branch-compare as data (so is not an manjaro announcement !)

url = "https://manjaro.org/branch-compare/packages.x86_64.json"

response = urllib.request.urlopen(url)
data = json.loads(response.read())['packages']
# pkg only in stable/testing and in "core" repo
data = [p for p in data if (p[1]['testing'] == "n/a" or p[1]['unstable'] == "n/a") and p[1]['repository'] == "core"]
eofs = set([p[0].split('#')[0] for p in data])  # want only names
print('EOL kernels:', eofs)