Our apps are closed-source, and we have no current plans to open-source them.
We have seen time and again, especially on Android, that whenever a moderately-popular app goes open-source, it is immediately picked up by unscrupulous developers. They download the source, add obnoxious ads (including pop-over ads, lock-screen ads, full-screen ads which we consider truly obnoxious). Then they add tracking code to log every single thing you do on your phone, including your location history, browsing history, etc so they can sell it to advertisers. Finally, they publish it to the Play Store without changing much of the original branding.
This hurts you — our users — because of the confusion caused by two or more similarly-named products with similar features.
It also hurts our brand, because now whoever downloads these malicious apps will associate the ads and other crapware with our brand. We treat our reputation very seriously and do not want to be tainted by anything like this.
We have no intention of enabling such people to cause harm to all of you, our valuable users, and to us.