* Develop static analysis [https://developer.mozilla.org/en-US/docs/DXR DXR] tool, then:
** Clean up uses of obsolete API. [[Gecko:Obsolete API]]
** [https://bugzilla.mozilla.org/show_bug.cgi?id=1022814 Automatically identify unused or hardly-used code].
** Ownership analysis:
*** Strong/weak pointers.