Al Fadi discusses more edits,corrections and modifications on one manuscript called the Doha;Qatar manuscript. First he gives four examples using Q 6:91-97. Second he talks about post production insertions using Q 5: 93; where an entire phrase was written on top of another.  You can listen for more details on the subject and also watch the 9 episode series on Cirainternational u-tube channel.  All this shows that the perfect preservation of the Quran as muslims claim is questionable.