Exodus is NOT 100% open source.
Many components inside Exodus are open source. You can view the source code to individual components on our Github repo.
If open source is a major source of impact for your choice in software Exodus is not for you. Good news is there are plenty of choices out there for 100% open source projects today.
We understand if having Exodus closed source makes you uncomfortable and we respect that. If that is the case please do not use Exodus.
We do hope to open source at some point in the future. Our technical co-founder JP is fanatical about open source.