`preamble-list-...`

The ... header is a correctly formatted comma-separated list.

Examples

error[preamble-list-requires]: preamble header list items must begin with a space
  --> input.md:11:13
   |
11 | requires: 20,1337,2048
   |             ^ missing space
   |                  ^ missing space
   |

Explanation

The preamble-list-... family of lints checks to make sure that front matter (or preamble) fields containing lists are formatted so other tools can understand them.

List items should be separated with a comma and a single space, for example: this, is, a, list.