custom-item-as-base

hint by default

A Book used where the game takes a plain item id, such as a recipe ingredient or an item tag. It stands for written_book there, so any written book matches.

Changing it

Set the rule's severity in mms.json, to error, warning, info, hint or off:

{
  "lint": { "custom-item-as-base": "off" }
}

To silence it on one line, write // mms-ignore custom-item-as-base on the line or the line above. See Lint rules in the guides for more.