tenfourfox
                                
                                 tenfourfox copied to clipboard
                                
                                    tenfourfox copied to clipboard
                            
                            
                            
                        Block top-level data: URIs
As a security measure.
See https://bugzilla.mozilla.org/show_bug.cgi?id=1331351 plus deps and followups (and/or PM1528).
Let's make sure #525 sticks before we implement this.