Since these are just interpreted comments, there's 0 impact on actual code.
This removes all lines that match /* vim: set(.*)tw=80: */ with S&R -- there are
a few others scattered around which will be removed manually in a second part.
Favor fallback content in that case (if present). Fallback is always
considered "good" in this case so may end up doing nothing which is what
we'd want for corner cases that hammer this routine with no content.
If a page uses or removes many <object> elements which are not actually plugins, loading the page goes to a crawl because UXP recalculates the plugin UI every time.
Only dispatch a PluginRemoved event for actual plugins.
This creates a number of stubs and leaves some surrounding code that may be irrelevant (eg. recorded time stamps, status variables).
Stub resolution/removal should be a follow-up to this.