= Big Important Note =
The We are currently waiting on the PNG group to approve our use of our chunks as public chunks (i.e. 2nd letter is capitalized.) Once they have approved the chunk names only the public chunk names in this specification will be changed to aCTl, fCTl valid and fDAtAPNGs created before that point will become invalid. Please consider any APNGs with acTl, -> aCTlfcTl and -> fCTlfdAt to be useless after that change happens.-> fDAt
= Overview =