What's the power density? (Amount of energy delivered over time)
That's not power density. That's just power. Power density is how much power (energy delivered over time) it can deliver per unit volume of battery. That's really only of concern for high power applications such as an electric race car. For most usages, energy density is far more valuable.
I'm not sure why you view changing a battery once or twice a year as such a big deal.
It's because it generally means replacing your whole phone these days.
The difference between project hosting and a "service to host and edit source code repositories" is a few wiki pages for a description and documentation.
You're forgetting about an issue tracker.
So your service will randomly fail to start, depending upon whether the local system's "init" just happened to start the services yours depends upon before your's?
That... doesn't seem like a good idea to me. While I'd certainly ensure my scripts handle the non-startup of dependencies gracefully, I'd definitely want a sane init system to actually know what to start up, and in what order.
Uh, no, the whole point is that the service checks for the dependency, and if it's met, then all good, and if it's not met, it requests the dependency to be started.