* Parallel layout
** '''Why Rust?''' Existing code from Servo, parallel performance.
* Replace the XML parser: {{bug|1611289}}
** '''Why Rust?''' Parses untrusted input, replaces expat, a 3rd-party library with a history of frequent security vulnerabilities.
* WebMIDI: {{bug|1201593}}, {{bug|1201596}}, {{bug|1201598}}