See T110869

*.ggpht.com is google cloud servers used by many people (including non-free media), so we may want to revert it being allowed on commons (Ifc2454c7) after the glam upload is done.

Its projected this should be done sometime in early october. Contact for the upload project is @Spinster

Personal opinion that other people might not agree with: Its not super time-sensitive that this gets reverted immediately after the glam project is done (although it should be done at some point). Uploading via url is very restricted to certain user groups, so its unlikely anyone at commons is going to abuse this. My understanding is that the primary purpose of the whitelist is in the case of a malicious user in control of the other server trying to exploit bugs in curl, which presumably is less of an issue since google controls these servers and not some unknown party.