2.5.2: Apps should be self-contained in their bundles, and may not read or write data outside the designated container area, nor may they download, install, or execute code which introduces or changes features or functionality of the app, including other apps. Educational apps designed to teach, develop, or allow students to test executable code may, in limited circumstances, download code provided that such code is not used for other purposes. Such apps must make the source code provided by the Application completely viewable and editable by the user.
Apple Developer Documentation Referenced: Section 2.5.2
Additionally, $99 per year is required for pushing updates.
If PojavLauncher is ever pushed to the App Store, you will know!