@supports selector(::-webkit-foo) {
	/* style to apply when the `::-webkit-foo` selector is actually supported,
	 * instead of just being parsed as matching nothing because of Selectors 4
	 * § Appendix B: https://drafts.csswg.org/selectors-4/#compat */
}

----------------------------------------------------

[
	["atrule", [
		["rule", "@supports"],
		["function", "selector"],
		["punctuation", "("],
		["selector-function-argument", [
			["pseudo-element", "::-webkit-foo"]
		]],
		["punctuation", ")"]
	]],
	["punctuation", "{"],
	["comment", "/* style to apply when the `::-webkit-foo` selector is actually supported,\r\n\t * instead of just being parsed as matching nothing because of Selectors 4\r\n\t * § Appendix B: https://drafts.csswg.org/selectors-4/#compat */"],
	["punctuation", "}"]
]

----------------------------------------------------

Checks for the selector function in @supports rules.
