Security Update bundles were released for Catalina and Mojave as well. The list of security fixes for the Big Sur update 11.3 has three entries mentioning Gate

Security Update bundles were released for Catalina and Mojave as well. The list of security fixes for the Big Sur update 11.3 has three entries mentioning Gatekeeper: https://support.apple.com/en-us/HT212325 https://support.apple.com/en-us/HT212325 ...whereas the list for Catalina has only one: https://support.apple.com/kb/HT212326 https://support.apple.com/kb/HT212326