Mozilla is still open source, even under that (actually incorrect) definition. The trademarked artwork is not required to build it.
Do you have to substitute other images, or can you just delete the files?
I ask because here's an equivalent from the Fedora license agreement, which makes things maybe a bit fiddly:
If User modifies the Software, then User must replace all images containing the "Fedora" trademark. [...] Merely deleting these files may corrupt the Software.
Slashdot Mirror
And a "Euro tunnel boring machine" which is an old garden hoe. High bid so far is 63 pounds. See item number 3285782833.
Search eBay for "tunnel boring machine" -- there are one or two more wacky auctions, including a model and a poem...
Do you have to substitute other images, or can you just delete the files?
I ask because here's an equivalent from the Fedora license agreement, which makes things maybe a bit fiddly: