It turns out some ad/analytics SDKs used by various proprietary Android apps can be disabled/kneecapped by adding meta-data entries to the apps AndroidManifest
In order for an app to read its meta-data from its own AndroidManifest it actuallly has to go through the getPackageManager() call
This means we can change the system package parser and simply add these variables to every app
This would hopefully make usage of proprietary apps more private, granted they are still proprietary and can very well simply ignore these

core/java/android/content/pm/PackageParser.java
parseMetaData
line 5526

data.putBoolean("batch_opted_out_by_default", true);
data.putBoolean("com.ad4screen.no_geoloc", true);
data.putBoolean("com.bugsnag.android.AUTO_CAPTURE_SESSIONS", false);
data.putBoolean("com.bugsnag.android.ENABLE_EXCEPTION_HANDLER", false);
data.putBoolean("com.bugsnag.android.PERSIST_USER_BETWEEN_SESSIONS", false);
data.putBoolean("com.bugsnag.android.SEND_THREADS", false);
data.putBoolean("com.facebook.sdk.AutoLogAppEventsEnabled", false);
data.putBoolean("com.followanalytics.message.inapp.enable", false);
data.putBoolean("com.followanalytics.message.push.enable", false);
data.putBoolean("com.mixpanel.android.MPConfig.AutoShowMixpanelUpdates", false);
data.putBoolean("com.mixpanel.android.MPConfig.DisableAppOpenEvent", true);
data.putBoolean("com.mixpanel.android.MPConfig.DisableDecideChecker", true);
data.putBoolean("com.mixpanel.android.MPConfig.DisableFallback", true);
data.putBoolean("com.mixpanel.android.MPConfig.DisableGestureBindingUI", true);
data.putBoolean("com.mixpanel.android.MPConfig.DisableViewCrawler", true);
data.putBoolean("com.mixpanel.android.MPConfig.TestMode", true);
data.putBoolean("com.mixpanel.android.MPConfig.UseIpAddressForGeolocation", false);
data.putBoolean("com.webengage.sdk.android.location_tracking", false);
data.putBoolean("engagement:adm:register", false);
data.putBoolean("engagement:locationReport:lazyArea", false);
data.putBoolean("engagement:locationReport:realTime:background", false);
data.putBoolean("engagement:locationReport:realTime", false);
data.putBoolean("engagement:locationReport:realTime:fine", false);
data.putBoolean("engagement:log:test", false);
data.putBoolean("engagement:reportCrash", false);
data.putBoolean("firebase_analytics_collection_deactivated", true);
data.putBoolean("firebase_analytics_collection_enabled", false);
data.putBoolean("firebase_crash_collection_enabled", false);
data.putBoolean("firebase_performance_collection_deactivated", true);
data.putBoolean("FYBEnableSSLRewardedVideo", true);
data.putBoolean("google_analytics_adid_collection_enabled", false);
data.putBoolean("mceSessionEnabled", false);
data.putBoolean("tapjoy.disable_video_offers", true);
data.putInteger("CLEVERTAP_USE_GOOGLE_AD_ID", 0)
data.putInteger("engagement:connection:delay", 2629800);
data.putString("apptentive_api_key", "");
data.putString("apptentive_key", "");
data.putString("apptentive_signature", "");
data.putString("__ChartboostAir__AppID", "");
data.putString("__ChartboostAir__AppSignature", "");
data.putString("com.ad4screen.facebook_appid", "");
data.putString("com.ad4screen.partnerid", "");
data.putString("com.ad4screen.privatekey", "");
data.putString("com.ad4screen.senderid", "");
data.putString("com.ad4screen.tracking_mode", "Restricted");
data.putString("com.appsee.ApiKey", "");
data.putString("com.blueshift.gcm_sender_id", "");
data.putString("com.google.android.awareness.API_KEY", "");
data.putString("com.pushwoosh.appid", "");
data.putString("com.pushwoosh.senderid", "");
data.putString("com.sprooki.LOCATION_SERVICES", "disable");
data.putString("com.upsight.app_token", "");
data.putString("com.upsight.public_key", "");
data.putString("FAID", "");
data.putString("io.branch.sdk.BranchKey", "");
data.putString("io.emma.SESSION_KEY", "");
data.putString("net.hockeyapp.android.appIdentifier", "");
data.putString("pilgrim_sdk_key", "");
data.putString("pilgrim_sdk_secret", "");
data.putString("presage_key", "");