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Google gives Android users a way to install unverified apps if they worked hard for it(including waiting 24 hours)
(android-developers.googleblog.com)
This is a most excellent place for technology news and articles.
Then you're just installing from the play store are you not? If you want to use f-droid or something else you initially have to start with getting their .apk do you not? Or am I mistaken and misremembering?