Than to extract information from .png?

Hi, guys. Situation: there are .png file, at the beginning there is xml code that I need. How to change it and then save those changes to the file? Or extract at least. An example of such a file:
709578683.png
July 4th 19 at 23:43
3 answers
July 4th 19 at 23:45
For example, HIEW can certainly cope with this task.
and Notepad - lilyan.Satterfie commented on July 4th 19 at 23:48
: Well, flag in hand binaries with Notepad edit... - Korbin.Jakubowski commented on July 4th 19 at 23:51
: I'm about to extract, edit in notepad++ - lilyan.Satterfie commented on July 4th 19 at 23:54
: Well, remove from the binary, Cho. - Korbin.Jakubowski commented on July 4th 19 at 23:57
: the text in the beginning is quite a text - lilyan.Satterfie commented on July 5th 19 at 00:00
July 4th 19 at 23:47
Well, you get the file, split it into pieces, then change the desired part and save everything to a new file. If he persists, then replace the original file.

How to split apart? The length in bytes or a marker (sign).
July 4th 19 at 23:49
There is a useful utility TweakPNG, it can help to extend/add any chunk of the png.

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