I have found that there are at least two different digital text editions of the KJV that have also been used in printed editions. Each of them has their own set of twenty or so variations from other typical KJV editions. One of them has been used by more different publishers. This more commonly used digital KJV text can be found in two forms, both with the same common group of new variations, but one with several additional ones. It would seem that either someone made some corrections to the original digital edition or else someone may have used one of the printed editions of it in making another digital edition, introducing more variations.
Be aware that KJV editions with the same copyright date may or may not be based on the digital text, depending on the actual year that they were printed. I have found that some publishers kept the same copyright date in their KJV edition when they switched over to printing it from a digital text edition, and they never seemed to realize that it differed in some places. Beginning at some point in 2014, Holman corrected most of these variations in their Holman KJV Study Bible personal size edition that came out in 2014 and in the bigger edition with the 2012 copyright date and perhaps in some of their other Holman editions.
Here is an example variation from one of the digital KJV texts with the KJV editions that I have found to have it.
Genesis 5:3
and after his image (1985 Visualized Bible) (1987 PSI) (1987, 2001, 2002 Thomas Nelson) (Jack Van Impe Prophecy Bible) (2003 Evidence Bible) (2004 World) (2005 ICC in Nashville) (2006 Paradise Press) (2008 Pilot) (2010, 2015 Baker) (2010 D & H Brothers) (American Patriot's Bible) (1979-2, 1996, 1998, 2010, 2013 Holman) (2011 AMProductions) (2011, 2012, 2015, 2016 Barbour) (2011 Prayer Journal Bible) (2012 Holman KJV Study Bible) (2012 Freeman-Smith) (2012 Woman's Study Bible by Thomas Nelson) (2014 Names of God Bible) (2015 KAPPA Books Publishers)
after his image (1769 Oxford, SRB) [1769 Cambridge, DKJB]
Here is an example variation from the other digital KJV text used by a few publishers:
Genesis 50:23
son Manasseh (2003 New Pilgrim Bible) (2001, 2002, 2003 Barbour) (2003 Inspirational Gift Company) (KJV Journaling Bible by Barbour) (2008, 2012 Rock of Ages Study Bible) (2009 Strand Study BIble)
son of Manasseh (1769 Oxford, SRB) [1769 Cambridge, DKJB]
Rock of Ages Study Bible was supposed to correct these variations in its new edition. I have heard that this new edition is now in print, but I have not seen one yet.