Has there been any discussion of CORS support in Mediawiki / WMF sites anywhere?
There was some talk of it in bug 32890 [0] in UploadWizard, and I tried to throw together code for it in a patchset [1], but I didn't spend much time on it (the effort was mostly to put the code into a workable patchset rather than just a snippet in a bug).
bawolff also commented on the patchset and linked to bug 20814 [2], which is further discussion of the topic in broader strokes.
[0] https://bugzilla.wikimedia.org/show_bug.cgi?id=32890 [1] https://gerrit.wikimedia.org/r/#/c/9718/ [2] https://bugzilla.wikimedia.org/show_bug.cgi?id=20814