As far as I can see, the binaries provided by the shadow package are displaying the macros in their man pages.
$ man lastlog
LASTLOG(8) System Management Commands LASTLOG(8)
.SH "NAME" lastlog - reports the most recent login of all users or of a given user
.PP lastlog formats and prints the contents of the last login log /var/log/lastlog file. The login-name, port, and last login time will be printed. The default (no flags) causes lastlog
entries to be printed, sorted by their order in /etc/passwd.
This problem occurs with these utilities, AFAIK:
$ pacman -Fl shadow | grep bin