--- /dev/null
+# selector-pseudo-class-no-unknown
+
+Disallow unknown pseudo-class selectors.
+
+```css
+ a:hover {}
+/** ↑
+ * This pseudo-class selector */
+```
+
+This rule considers pseudo-class selectors defined in the CSS Specifications, up to and including Editor's Drafts, to be known.
+
+All vendor-prefixed pseudo-class selectors are ignored.
+
+## Options
+
+### `true`
+
+The following patterns are considered violations:
+
+```css
+a:unknown {}
+```
+
+```css
+a:UNKNOWN {}
+```
+
+```css
+a:hoverr {}
+```
+
+The following patterns are *not* considered violations:
+
+```css
+a:hover {}
+```
+
+```css
+a:focus {}
+```
+
+```css
+:not(p) {}
+```
+
+```css
+input:-moz-placeholder {}
+```
+
+## Optional secondary options
+
+### `ignorePseudoClasses: ["/regex/", "string"]`
+
+Given:
+
+```js
+["/^my-/", "pseudo-class"]
+```
+
+The following patterns are *not* considered violations:
+
+```css
+a:pseudo-class {}
+```
+
+```css
+a:my-pseudo {}
+```
+
+```css
+a:my-other-pseudo {}
+```