kangax/compat-table — pull request #219 by webbedspace (2014-08-21 13:35:15+00:00)
Title: Altered WeakMap note regarding WeakSet in Firefox

FF Nightly 34's WeakSet allows constructor arguments, even though WeakMap seemingly doesn't - `new WeakSet([Math]).has(Math)` returns true, even though `new WeakMap([[Math,1]]).has(Math)` doesn't.