NoNetherTraveling This plugin blocks your players from traveling above the roof in the nether world(s).
A simple config.yml allows you to set the warning message and the damage to apply per second. Admins may bypass warnings and damage with permission "nnt.bypass"
Support: Java 8 and above, Spigot 1.13 to 1.20 -----------------------------------------------------
This plugin is an original project that I started 4 years ago, thanks for all the people who use it!