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Japan to crack down on Apple and Google app store monopolies
(asia.nikkei.com)
This is a most excellent place for technology news and articles.
To add to other replies, play store protect flags apps with same names but different keys. This can cause false positives for security issues that pop up, I believe f-droid signs with keys generated through their system so they don't match a play store version. Users then could think it's a virus from f-droid and use play store instead.