To reformat a thing so it reads better. Prettifying changes presentation and must not change content.
From Old English prættig (cunning, skillful, later attractive) with -ify (Latin -ficare, to make); to reformat a thing so it reads better, changing only how it looks and never what it says.
To reformat a thing so it is easier to read, changing only how it presents and never, if it is done honestly, what it actually says.