Are you saying it definitely is NOT in the IIci ROM?
The one ting the IIci and fx have in common is that they were the first 512K 32-bit clean ROMs. However, the Classic was essentially the 256K SEFDHD ROM with an embedded System RAM disk, accounting for the other 256K, plus a software screen dimming feature. Paul Pratt details this somewhat on his Mini vMac documentation about the Classic.
So I would not be surprised if this was not developed for the 32-bit clean ROMs to set them apart from the old dirty ROMs and never implemented. But I would expect it to show up in the IIci then, which is otherwise the same interchangeable ROM software as the IIfx. Perhaps the IIfx got the idea to help set it apart during startup from the earlier IIx which was notoriously dirty, since the case was otherwise identical?
I took a look at this on Mini vMac and I don't see anything but the static image, either with a System disk or the embedded System. I doubt it would be different on a real Classic. However, the Classic failed to implement many aspects of its intended functions. It occurred to me that this might have been intended to be implemented to differentiate startup between the embedded system and that of the hard drive, or floppy (Apple was notoriously subtle with such distinctions, as in the single pixel in the wIndow bar between HFS & MFS systems).