As a fun project, I started developing an Android app for myself a few weeks ago, because I already missed Boost for Reddit, even though it's still usable. So I took Boost as an inspiration and started working. It's come quite far and I have decided to publish it on Google Play, in case others feel the same way. It's still lacking some features, most notably the ability to see when someone sent you a message or replied to your comments, as well as the ability to create posts, but for casual lurking it's already quite nice I think. It will hit Play Store in a fews days.
Will it be open-source?
I'm not sure yet. Right now it's not, but if the majority of people wants it to be then I'd oblige. I have zero experience with managing open source projects though, so I'm not sure if it's a good idea
As @[email protected] already said, a non open source app will probably have acceptance issue, getting away from a proprietary app is the reason why many people are here in first place :) .
One of the most important things about open sourcing code is to find a well suited license and it's not just about choosing any license but to also have all the dependencies in mind. But I'm sure the people for example at [email protected] would be glad to help you if you want assistance in choosing an appropriate license.
Other than that, managing (small) open source projects is actually pretty chill.