How do you know you can trust instagram/google maps/ any other common app on your phone?
I would trust German government way more than i trust just about any corporate entity I can think of.
However, since this is a tracing app and being open source would imply "look, our app is clean, check our code if you do not trust us". Off-course making it open source has other benefits too.
> How do you know you can trust instagram/google maps/ any other common app on your phone?
I don't. If I am using it I know that I have no way to validate or enforce what happens with my data.
To add, there are currently discussions underway in the German parliament to give our secret services (namely the notorious Verfassungsschutz) the power to compromise IT systems (Bundestrojaner). I'd trust even the government not that much these times.
As for conpromising IT systems, arent they just going to bw on a level playing field with NSA and others?