Just a note: this icon is not specific to Transmogrified. It's the default icon used throughout the site (see http://www.dreamwidth.org/support/faqbrowse.bml?faqid=133).

In this case, though, DW is trying to pre-empt an icon that has a well-established meaning.

Not well-established to me. I've never used the software you mention. Just saying; I'm actually using my own icons.