It seems to be poorly documented what non/low/medium/high mean in terms of linter categories.
One can work out from the `CategoryManager` that none is not visible, the rest are:
```lang=php
private const HIGH = 'high';
private const MEDIUM = 'medium';
private const LOW = 'low';
private const NONE = 'none';
/**
* Categories that are configured to be displayed to users
*
* @return string[]
*/
public function getVisibleCategories() {
return array_merge(
$this->categories[self::HIGH],
$this->categories[self::MEDIUM],
$this->categories[self::LOW]
);
}
/**
* Categories that are configured to not be displayed to users
*
* @return string[]
*/
public function getInvisibleCategories() {
return $this->categories[self::NONE];
}
```
Similar goes for the the various `config` items in `extension.json`. Again, specifically `LinterCategories`.
Ideally they should be documented inline, as appropriate, and also on https://www.mediawiki.org/wiki/Extension:Linter