1-keep interface android.annotation.SystemApi
2-keep @android.annotation.SystemApi public class * {
3    public protected *;
4}
5-keepclasseswithmembers public class * {
6    @android.annotation.SystemApi public protected *;
7}
8# Also ensure nested classes are kept. This is overly conservative, but handles
9# cases where such classes aren't explicitly marked @SystemApi.
10# TODO(b/248580093): Rely on Metalava-generated Proguard rules instead.
11-if @android.annotation.SystemApi class *
12-keep public class <1>$** {
13    public protected *;
14}
15