Yes, it's a perfect thing to include in the title because using just 2 words I can say:

- It's free to use

- You can request new features, and there is a good chance that they'll be implemented

- There is no tracking = full privacy

- You can add features on your own if you know the platform

- If you learn Swift programming, you can check out the project and learn something from it

- If you are willing to become a contributor, you can join

This is an interesting question and I think for me open-source on the Mac usually means it’s hard to manage? It might use lots of CLI and config files and libraries and be more Lennox focused. This is fine of course, but I wouldn’t say it’s how you advertise to a Mac user. For me the best Mac apps are made by small focused teams with a passion for the product that they are making with an eye towards customer usability.

Free vs paid subscription