Atom MDN Doc is a package allows you to consult the documentation in the Mozilla Developer Network MDN
apm install mdn-doc
Preferences > Install, search for
mdn-doc and install it.
Mark or place your cursor over a word or property and use:
Cmd + Shift + Pto open command palette and choose MDN Doc
Good catch. Let us know what about this package looks wrong to you, and we'll investigate right away.