`launchctl export` doesn't work

According to the man page of

launchctl

export

export   Export all of the environment variables of launchd forusein a shell eval statement.

However, when I try to use this command, I get the following message.

Unrecognized subcommand:exportUsage: launchctl <subcommand>...| help [subcommand]

What's going on here? Did the command exist at some point, but was removed for some reason, and someone forgot to update the man page? If so, I'd certainly like to request that command be readded – it's very useful indeed for debugging purposes, among others.