This plugin is all about making creepers drop records. Pretty basic.
Why? In the default game, there are now 11 records available, but in the past only the original first two (green and gold) were dropped by creepers when they were killed by skeletons. The other 9 records didn't show up in the game. This now appears to be fixed in current releases of Minecraft so that 10 of the 11 records can be dropped this way. So, that functionality of this plugin is now removed.
What This Mod Actually Does
When a creeper is killed, it will now have a small chance of dropping a random record without needing to be killed by a skeleton. By default this can only happen when killed by a player and is then only a 3% chance (1 in 33.3). Note that this chance only applies when a player directly kills the creeper by sword or projectile (arrows and potions should work), so mob farms and such won't make them drop records.
Drop it in your plugins folder, the same way you install every other server plugin.
If you change the configuration, you will need to restart your server to see the effect.
The options in config.yml are as follows:
record_drop_percentage: percentage chance of creepers randomly dropping a record (assuming they're not already dropping one from being killed by a skeleton). Valid range is 0.0 to 100.0.
player_kills_only: whether the random record drops will only occur if the creeper is directly killed by a player; if false, any creeper deaths (such as by mob farm) will be accepted. Creepers exploding do not count as deaths regardless of this setting.
There's obviously not much to it, but the source is available here on GitHub.