Bukkit

What is "pvplogging"?

It means to avoid being killed by another player by disconnecting from the server, and reconnecting at a later time, presumably when the attacker has gone away.

How does this plugin attempt to stop that behaviour?

When a player is attacked (includes being shot with an arrow) by another player, the victim is tagged as "in-combat" for 5 seconds (configurable). If the victim disconnects while being tagged, he is killed (right away, not when he logs back in), dropping his inventory.

A message is sent to the victim when tagged, and after he is no longer tagged (the messages warn the player not to disconnect).
The attacker also gets notified, but only when he tags the victim, not when the tag is removed.
If a player does log out while being tagged and is killed, the death message announces that he was killed for pvplogging, for everyone on the server to see.

The attack check is done with lowest possible priority, so if other plugins cancel the attack it will not be registered as pvplogging (example: safezone in Factions plugin).
The in-combat tag time is configurable, messages too, and you may set a custom color for all death messages.

What configuration/commands/permissions are there?

The configuration is created automatically upon first run. See default KillPvPLoggers/config.yml.
In the "messages" node, $1 will be replaced by the other player's name (either victim or attacker, relative to message).

No commands. Reload or restart server to apply changes to config.yml.

No permissions.

Common pitfalls

No OP nor Creative-mode check! That means that admins could potentially be killed - I currently do not plan to add any of those checks, although they should be fairly easy to implement.

Kicked players get killed! Beware specially NoCheatPlus and similar plugins, when configured to kick offenders, they will most probably get killed since most offenses are triggered by combat. This is of course great to punish cheaters, but it can RUIN your server if it's a false positive (innocent person who lags or whatever). Solution: Do not enable kicks for NCP offenses and investigate manually (as NCP is configured by default).

Source is at github!