Maker Notes

Camera manufacturers usually want to enhance EXIF metadata with their own custom information. This may be a camera specific setting, camera identification, current environment, and others.

Maker notes are stored inside EXIF metadata in a special section. And these information are always defined by the manufcturer. The maker notes are not published, so only a reverse engineered subset of tags is known.

Also note that because these tags are non-standard, the fact that they are included in the EXIF metadata is also non standard, so there is no way to know which manufacturer's metadata are present except identification by Maker tag. So, if you want to clear this tag, you should also know that it will make maker notes inaccessible.