Man pages matching name image::exiftool::writepng in section 3pm:

Image::ExifTool::WritePNG.3pm.en	debian 10 / libimage-exiftool-perl
Image::ExifTool::WritePNG.3pm.en	debian 11 / libimage-exiftool-perl
Image::ExifTool::WritePNG.3pm.en	debian 12 / libimage-exiftool-perl