+++ This bug was initially created as a clone of Bug #577447 +++

When a newly visited page specifies data:image/x-icon with no content as its favicon, it inherits the favicon from the previously visited page.

I've noticed this a while ago with https://savitarna.perlasgo.lt/, but I've just reported them that their favicon is missing, so I hope they might fix this soon, so I'm attaching a really minimal test case which illustrates the problem.

If you visit a website that has a favicon (e.g. https://www.google.com), and then open the attached file in that same tab, you'll see that the tab keeps the favicon that was previously shown.

The severity field is not set for this bug.
:dao, could you have a look please?

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This is a screenshot of the Firefox tab's DOM at the time that the bug is reproduced. The src on the image looks pretty fishy - it's data:image/x-icon, which isn't a valid Data URI, and yet the old image is still displaying.

mak said he wanted to take a look at this.