Clear laucher defaults programmatically

Question

I am trying to delete default laucher parameters (to let user choose another app) with android.permission.SET_PREFERRED_APPLICATIONS. I googled that this is not pos

Answer 1

I am trying to delete default laucher parameters (to let user choose another app)

That is no longer possible.

there is a kidzone app (http://www.kidzoneapp.com/ see youtube video) that uses this technology.

It does on older versions of Android, where this was allowed.

Moreover it does it with the same permission in manifest.

Nowadays, that permission is no longer used, and it can only be held by applications signed by the same signing key as was used to sign the firmware.