The library is used to compress large documents before
sending to the server, as HTTP doesn't support upload compression.
(See T68914 for context.)
N.B. Many of the polyfills in the original are omitted as
MediaWiki doesn't support browsers which require them.
Co-Authored-by: Kunal Mehta <legoktm@member.fsf.org>
Change-Id: I12a5879188f46f17dc4c33bdad52317d218d4172
