Making JS extensions seems kind of limiting in a way, and I'm wondering what all the devs here feel like they're missing.
I'd like to investigate NPAPI plugins, and I'm thinking of making one that implements the missing features for use in extensions without the extra work of having to write your own NPAPI plugin.

At the moment, this is what I have planned for it:

• Downloads
• Scrollbar colour changing
• Theming button images
• Client-side preprocessing (PHP?)

Keep in mind these are entirely tentative, and I will be TRYING to implement them, it just depends how possible they are. Just kinda want to get a to-do list together before starting.