Java Edition:Long World Name
While a world name is normally limited to 32 characters, there is a method that allows for world names over 32 characters from 12w18a (1.3 snapshot) to 20w16a (1.16 snapshot).
Obtaining
When creating a new world, if the name picked matches a current world folder name, additional characters will be added to the new folder name. The actual world name will only be the original picked name, which must be within the 32 character limit. However, if the game closes out while generating the world, the folder name will be applied to the world name, regardless of the folder name length. From 12w18a through 19w11b, world names would uses dashes after the name, and from 19w12a+ a number in parentheses is added to the end. The longest possible name is a bit complicated to figure out, since it is limited to the longest possible folder name, and the maximum length of the folder name is determined by the length of the file path, which is limited to 248 characters. Due to the version range, the long name is mutually exclusive with formatted world names.