[Solved] PNG conversion metadata: Apple Data Offsets field disappears

[es]

I've noticed when converting a screenshot that exiftool shows has the following field

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Apple Data Offsets : (Binary data 28 bytes, use -b option to extract)

after conversion disappears and there is this Comment instead

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Comment : iDOT chunklen 28 ignored:.ASCII: ...........©...(...©...©...#.HEX: 0000000200000000000000A900000028000000A9000000A900001523

Don't know what this field is, google surprisingly gives only 1 result for it, so I'd say it's something useless, but I'm just worried a bit that there might be a more general issue in metadata conversion during image editing which might lead to a loss of something more useful
Is there a way to maybe just preserve those chunks/tags instead of ignoring them?

[forum_adm]

Here is a helpful detail:
https://stackoverflow.com/questions/338 ... idot-chunk

It is not a standard chunk. GraphicConverter does not write it upon resaving the file.

[es]

Oh, I see, the "Apple data offset" is exiftool naming, that's why couldn't find anything about it
Thanks for the clarification!

However, given the fact that the PNG spec requires removing such chunks on conversion (due to capitalized T), maybe this fact should just be mentioned in the Comment without carrying the now useless value?
(Or maybe it shouldn't be mentioned at all? Not sure)

[forum_adm]

I added now a preference to build 6015:

Screenshot 2023-02-28 at 06.35.jpg (94.85 KiB) Viewed 2574 times

[es]

Thank you!