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/com/facebook/shimmer/ShimmerFrameLayout.java

@@ -0,0 +1,133 @@
+package com.facebook.shimmer;
+
+import R1.a;
+import R1.b;
+import R1.c;
+import R1.d;
+import android.animation.ValueAnimator;
+import android.content.Context;
+import android.content.res.TypedArray;
+import android.graphics.Canvas;
+import android.graphics.Paint;
+import android.graphics.PorterDuff;
+import android.graphics.PorterDuffXfermode;
+import android.graphics.drawable.Drawable;
+import android.util.AttributeSet;
+import android.widget.FrameLayout;
+import com.google.android.gms.maps.model.BitmapDescriptorFactory;
+
+/* loaded from: classes3.dex */
+public class ShimmerFrameLayout extends FrameLayout {
+
+    /* renamed from: a, reason: collision with root package name */
+    public final Paint f5504a;
+
+    /* renamed from: b, reason: collision with root package name */
+    public final d f5505b;
+
+    /* renamed from: c, reason: collision with root package name */
+    public final boolean f5506c;
+
+    public ShimmerFrameLayout(Context context, AttributeSet attributeSet) {
+        super(context, attributeSet);
+        b bVar;
+        this.f5504a = new Paint();
+        d dVar = new d();
+        this.f5505b = dVar;
+        this.f5506c = true;
+        setWillNotDraw(false);
+        dVar.setCallback(this);
+        if (attributeSet == null) {
+            a(new b(0).b());
+            return;
+        }
+        TypedArray obtainStyledAttributes = context.obtainStyledAttributes(attributeSet, a.f1416a, 0, 0);
+        try {
+            if (obtainStyledAttributes.hasValue(4) && obtainStyledAttributes.getBoolean(4, false)) {
+                bVar = new b(1);
+                ((c) bVar.f267a).p = false;
+            } else {
+                bVar = new b(0);
+            }
+            a(bVar.c(obtainStyledAttributes).b());
+            obtainStyledAttributes.recycle();
+        } catch (Throwable th) {
+            obtainStyledAttributes.recycle();
+            throw th;
+        }
+    }
+
+    public final void a(c cVar) {
+        boolean z3;
+        d dVar = this.f5505b;
+        dVar.f1440f = cVar;
+        if (cVar != null) {
+            dVar.f1436b.setXfermode(new PorterDuffXfermode(dVar.f1440f.p ? PorterDuff.Mode.DST_IN : PorterDuff.Mode.SRC_IN));
+        }
+        dVar.b();
+        if (dVar.f1440f != null) {
+            ValueAnimator valueAnimator = dVar.f1439e;
+            if (valueAnimator != null) {
+                z3 = valueAnimator.isStarted();
+                dVar.f1439e.cancel();
+                dVar.f1439e.removeAllUpdateListeners();
+            } else {
+                z3 = false;
+            }
+            c cVar2 = dVar.f1440f;
+            ValueAnimator ofFloat = ValueAnimator.ofFloat(BitmapDescriptorFactory.HUE_RED, ((float) (cVar2.f1434t / cVar2.f1433s)) + 1.0f);
+            dVar.f1439e = ofFloat;
+            ofFloat.setRepeatMode(dVar.f1440f.f1432r);
+            dVar.f1439e.setRepeatCount(dVar.f1440f.f1431q);
+            ValueAnimator valueAnimator2 = dVar.f1439e;
+            c cVar3 = dVar.f1440f;
+            valueAnimator2.setDuration(cVar3.f1433s + cVar3.f1434t);
+            dVar.f1439e.addUpdateListener(dVar.f1435a);
+            if (z3) {
+                dVar.f1439e.start();
+            }
+        }
+        dVar.invalidateSelf();
+        if (cVar == null || !cVar.f1429n) {
+            setLayerType(0, null);
+        } else {
+            setLayerType(2, this.f5504a);
+        }
+    }
+
+    @Override // android.view.ViewGroup, android.view.View
+    public final void dispatchDraw(Canvas canvas) {
+        super.dispatchDraw(canvas);
+        if (this.f5506c) {
+            this.f5505b.draw(canvas);
+        }
+    }
+
+    @Override // android.view.ViewGroup, android.view.View
+    public final void onAttachedToWindow() {
+        super.onAttachedToWindow();
+        this.f5505b.a();
+    }
+
+    @Override // android.view.ViewGroup, android.view.View
+    public final void onDetachedFromWindow() {
+        super.onDetachedFromWindow();
+        d dVar = this.f5505b;
+        ValueAnimator valueAnimator = dVar.f1439e;
+        if (valueAnimator == null || !valueAnimator.isStarted()) {
+            return;
+        }
+        dVar.f1439e.cancel();
+    }
+
+    @Override // android.widget.FrameLayout, android.view.ViewGroup, android.view.View
+    public final void onLayout(boolean z3, int i, int i4, int i5, int i6) {
+        super.onLayout(z3, i, i4, i5, i6);
+        this.f5505b.setBounds(0, 0, getWidth(), getHeight());
+    }
+
+    @Override // android.view.View
+    public final boolean verifyDrawable(Drawable drawable) {
+        return super.verifyDrawable(drawable) || drawable == this.f5505b;
+    }
+}