I used to use many apps from Simple Mobile Tools and migrated to Fossify's forks when the whole acquisition thing happened. I just went back to check the Simple Mobile Tools to see the effect form ZipooApps' acquisition [1]. What a calamity. Most of them require way more permissions than they used to before the purchase, have trackers, ads and scam-feeling weekly subscriptions. Also probably in breach of the GPL licence they used to have, unless they have removed all the code contributed by third parties, as their GitHub [2] hasn't been updated, but the apps in the Play Store clearly have. And I seriously doubt they distribute the source code in any other way.
1: https://play.google.com/store/apps/dev?id=821434617619498026...
2: https://github.com/SimpleMobileTools