For me it doesnt work... here is the error:

Could not load 'plugins/CustomSleeping-6.1.jar'
in folder 'plugins'
org.bukkit.plugin.InvalidDescriptionException: Invalid plugin.yml
at org.bukkit.plugin.java.JavaPluginLoader.getPluginDescri
ption(JavaPluginLoader.java:178) ~[paper-api-1.18.1-R0.1-SNAPSHOT.
jar:?] at org.bukkit.plugin.SimplePluginManager.loadPlugins(Simp
ePluginManager.java:158) ~[paper-api-1.18.1-R0.1-SNAPSHOT.jar:?]
at org.bukkit.craftbukkit.v1_18_R1.CraftServer.loadPlugins (CraftServer.java:421) ~[paper-1.18.1.jar:git-Paper-68]
at net.minecraft.server.dedicated.DedicatedServer.initServ
er(DedicatedServer.java:285) ~[paper-1.18.1.jar:git-Paper-68]
at net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:1202) ~[paper-1.18.1.jar:git-Paper-68]
at net.minecraft.server.MinecraftServer.lambda$spin$0(Mine
craftServer.java:317) ~[paper-1.18.1.jar:git-Paper-68]
at java.lang.Thread.run(Thread.java:833) ~[?:?]
Caused by: java.io.FileNotFoundException: Jar does not contain plugin.yml

It weighs very little, does not load the system, does what it should.
There are no annoying messages, all messages can be changed in the configuration.

Excellent Plugin. Easy to use and Frequently updated.
Author is willing to help. nice.

A great, lightweight plugin that makes it easy for players to sleep, especially on servers with 10+ people.