Yes, I made two small contributions till now. The maintainers seem pretty responsive when new PRs are opened and open to the stuff people are adding. Did not have a thorough look through all the code of the app yet but what I have seen seems structured quite good and I look forward to working more with Kotlin and Jetpack Compose. Am a Java Dev for work, quite some time since I last worked on an Android App but making small contributions first should get you started