Moderation

effectkick <who> [because <text>]since 1.5.7

Disconnect a player with a message

kick arg.1 because "&cPlease calm down."

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effectban <who> [for <duration>] [because <text>]since 1.5.7

Ban by name, for good or for a while, and kick them if online

ban arg.1 for 7 days because "&cGriefing"

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effectunban <who>since 1.5.7

Lift a ban

unban arg.1

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condition<who> is banned / is not bannedsince 1.5.7

A condition

if arg.1 is not banned:
    send "&7%arg.1% is not banned."

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effectrefuse login [because <text>]since 1.5.7

Inside on player login:, turn the player away

on player login:
    if {maintenance}:
        refuse login because "&eBack soon!"

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Guide and examples

command /mute-kick <player>:
    permission: "staff.kick"
    trigger:
        kick arg.1 because "&cPlease calm down."

on player login:
    if {maintenance} and {%player%.staff} is not set:
        refuse login because "&eThe server is being worked on. Back soon!"

Syntax	Effect
`kick <who> [because <text>]`	Disconnect a player with a message
`ban <who> [for <duration>] [because <text>]`	Ban by name, for good or for a while, and kick them if online
`unban <who>`	Lift a ban
`<who> is banned` / `is not banned`	A condition
`refuse login [because <text>]`	Inside `on player login:`, turn the player away

ban ... for 7 days ends by itself. Without for, the ban lasts until unban.
Bans are the server's own (the same list /ban and /pardon use), so they work for players who are offline and survive restarts.
on player login: runs while someone is connecting, before they are in the game. There is no player yet, so send reaches nobody and player.name is unset; use %event.name% for their name. {%player%.<name>} does work and is the variables of whoever is logging in, which is what makes checks such as a ban of your own or a whitelist possible.