This is so minor it may as well be trivial, but would also be (presumably) a small fix: could the MIME type Marketo serves for icon files (.ico) be updated so it uses image/x-icon? Right now, icon files are served as text/plain, which recently contributed to some confusion when someone loaded the icon directly from the URL.
This, of course, does not affect in-browser renderings of favicons, etc., so this is an edge case.
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