It's not really used interchangeably: "bug" is used to mean "entry in the bug tracker database", while "feature" is used to mean what we colloquially think of as a feature of a computer program.

It's arguably a slight abuse of a bug tracking system to also track progress and discussion on features, but it's not exactly uncommon; it's just that many systems would call it an "issue" rather than a "bug".

Maybe more like a heading bug:

https://aviation.stackexchange.com/questions/23166/what-is-t...

Google's internal issue tracker, Buganizer (which the Chromium Issue Tracker is based on), refers to everything as a "bug". It's confusing, yeah. You get used to it.

Not really -- they're all "potential todos" that need to be tracked and prioritized in the same place.

And the difference between a bug and a feature is often in the eye of the beholder. I'll very often title a GitHub issue with "Bug/Feature Request:" since it's often debatable whether the existing behavior was by design or not, and I don't want to presume one way or the other.

So I do consider them all pretty interchangeable at the end of the day, and therefore not really confusing.