/etc/apparmor.d/usr.sbin.mysqld-akonadi is in akonadi-backend-mysql 4:17.12.3-0ubuntu3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 | # vim:syntax=apparmor
#include <tunables/global>
/usr/sbin/mysqld-akonadi {
  #include <abstractions/base>
  /usr/sbin/mysqld-akonadi r,
  /usr/sbin/mysqld cx,
  profile /usr/sbin/mysqld {
    #include <abstractions/base>
    #include <abstractions/nameservice>
    #include <abstractions/user-tmp>
    capability setgid,
    capability setuid,
    /etc/mysql/conf.d/ r,
    /etc/mysql/conf.d/* r,
    /etc/mysql/my.cnf r,
    /sys/devices/system/cpu/ r,
    /usr/sbin/mysqld mr,
    /usr/share/mysql/** r,
    @{HOME}/.local/share/akonadi/** rwk,
    # Site-specific additions and overrides. See local/README for details.
    #include <local/usr.sbin.mysqld-akonadi>
  }
}
 |