Primer paso de la investigacion. Se aportan el .apk, las carpetas con el apk extraido y el apk descompilado. El archivo API_DOCUMENTATION.md es un archivo donde se anotaran los descubrimientos del funcionamiento de la API, y los .py son scripts para probar la funcionalidad de la API con los métodos que vayamos encontrando. Finalmente, los archivos .js son scripts de Frida para extraer informacion de la APP durante la ejecucion.

apk_decompiled/sources/kotlin/reflect/jvm/internal/impl/SpecialJvmAnnotations.java

@@ -0,0 +1,70 @@
+package kotlin.reflect.jvm.internal.impl;
+
+import java.util.Iterator;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Set;
+import kotlin.collections.CollectionsKt;
+import kotlin.jvm.internal.Intrinsics;
+import kotlin.jvm.internal.Ref;
+import kotlin.jvm.internal.SourceDebugExtension;
+import kotlin.reflect.jvm.internal.impl.descriptors.SourceElement;
+import kotlin.reflect.jvm.internal.impl.load.java.JvmAbi;
+import kotlin.reflect.jvm.internal.impl.load.java.JvmAnnotationNames;
+import kotlin.reflect.jvm.internal.impl.load.kotlin.KotlinJvmBinaryClass;
+import kotlin.reflect.jvm.internal.impl.name.ClassId;
+import kotlin.reflect.jvm.internal.impl.name.FqName;
+
+@SourceDebugExtension({"SMAP\nSpecialJvmAnnotations.kt\nKotlin\n*S Kotlin\n*F\n+ 1 SpecialJvmAnnotations.kt\norg/jetbrains/kotlin/SpecialJvmAnnotations\n+ 2 _Collections.kt\nkotlin/collections/CollectionsKt___CollectionsKt\n*L\n1#1,42:1\n1620#2,3:43\n*S KotlinDebug\n*F\n+ 1 SpecialJvmAnnotations.kt\norg/jetbrains/kotlin/SpecialJvmAnnotations\n*L\n22#1:43,3\n*E\n"})
+/* loaded from: classes3.dex */
+public final class SpecialJvmAnnotations {
+    public static final SpecialJvmAnnotations INSTANCE = new SpecialJvmAnnotations();
+    private static final ClassId JAVA_LANG_ANNOTATION_REPEATABLE;
+    private static final Set<ClassId> SPECIAL_ANNOTATIONS;
+
+    static {
+        List listOf = CollectionsKt.listOf((Object[]) new FqName[]{JvmAnnotationNames.METADATA_FQ_NAME, JvmAnnotationNames.JETBRAINS_NOT_NULL_ANNOTATION, JvmAnnotationNames.JETBRAINS_NULLABLE_ANNOTATION, JvmAnnotationNames.TARGET_ANNOTATION, JvmAnnotationNames.RETENTION_ANNOTATION, JvmAnnotationNames.DOCUMENTED_ANNOTATION});
+        LinkedHashSet linkedHashSet = new LinkedHashSet();
+        Iterator it = listOf.iterator();
+        while (it.hasNext()) {
+            linkedHashSet.add(ClassId.topLevel((FqName) it.next()));
+        }
+        SPECIAL_ANNOTATIONS = linkedHashSet;
+        ClassId classId = ClassId.topLevel(JvmAnnotationNames.REPEATABLE_ANNOTATION);
+        Intrinsics.checkNotNullExpressionValue(classId, "topLevel(...)");
+        JAVA_LANG_ANNOTATION_REPEATABLE = classId;
+    }
+
+    private SpecialJvmAnnotations() {
+    }
+
+    public final ClassId getJAVA_LANG_ANNOTATION_REPEATABLE() {
+        return JAVA_LANG_ANNOTATION_REPEATABLE;
+    }
+
+    public final Set<ClassId> getSPECIAL_ANNOTATIONS() {
+        return SPECIAL_ANNOTATIONS;
+    }
+
+    public final boolean isAnnotatedWithContainerMetaAnnotation(KotlinJvmBinaryClass klass) {
+        Intrinsics.checkNotNullParameter(klass, "klass");
+        final Ref.BooleanRef booleanRef = new Ref.BooleanRef();
+        klass.loadClassAnnotations(new KotlinJvmBinaryClass.AnnotationVisitor() { // from class: kotlin.reflect.jvm.internal.impl.SpecialJvmAnnotations$isAnnotatedWithContainerMetaAnnotation$1
+            @Override // kotlin.reflect.jvm.internal.impl.load.kotlin.KotlinJvmBinaryClass.AnnotationVisitor
+            public KotlinJvmBinaryClass.AnnotationArgumentVisitor visitAnnotation(ClassId classId, SourceElement source) {
+                Intrinsics.checkNotNullParameter(classId, "classId");
+                Intrinsics.checkNotNullParameter(source, "source");
+                if (!Intrinsics.areEqual(classId, JvmAbi.INSTANCE.getREPEATABLE_ANNOTATION_CONTAINER_META_ANNOTATION())) {
+                    return null;
+                }
+                Ref.BooleanRef.this.element = true;
+                return null;
+            }
+
+            @Override // kotlin.reflect.jvm.internal.impl.load.kotlin.KotlinJvmBinaryClass.AnnotationVisitor
+            public void visitEnd() {
+            }
+        }, null);
+        return booleanRef.element;
+    }
+}