Layout test fast/attachment/attachment-without-appearance.html is failing for GTK since it was added in r225252 "Allow attachment elements with no appearance to defer rendering to child nodes". Updating expectations accordingly. There is an image diff: https://build.webkit.org/results/GTK%20Linux%2064-bit%20Release%20(Tests)/r225484%20(4523)/fast/attachment/attachment-without-appearance-diffs.html I see two green squares, and the test says that means it's a pass. But they're not in the same place as in the reference image.
Ms2ger, I've moved this expectation to a new bug, since it's a new failure. Also, be sure to use the ImageOnlyFailure expectation when there is no text diff. I know that is a bit confusing. :/
There are no references to this bug in any TestExpectations. It's probable this bug was solved at some point but it wasn't marked as closed. I'm closing this bug now. If you think this bug report is still valid, please reopen it and add an entry to TestExpectations.