When editing the config file on a server, there is this setting:

// The rarity of the enchantment
"rarity": "RARE",

It is not clear to the person editing the file what text strings are valid in this field.

As far as I can tell, the possible values are the Rarity values listed in the source code of net\minecraft\enchantment\Enchantment.java, but most server owners won't go to the MC source code.

Suggestion is to add the possible values to the comment text.

// The rarity of the enchantment ("COMMON", "UNCOMMON", "RARE", "VERY_RARE")
"rarity": "RARE",