Our Apps and Open Source — Chimbori
chimbori.com
Some components of our apps are open-source, but the main apps are not. This is to protect you and us from unscrupulous counterfeiters who add malware and ads to open-source apps.

I am not following these claims carefully, but I have seen tons of copies of Lawnchair in the Playstore.

Another recent event that comes to my mind is the Simple apps, which AFAIK they always were open source? But that didn’t matter until it got sold and then Fossify was the non shit version of it (the positive side of open source).