The tag is present in Lintian version 2.109.24. That is the most recent version we know about.
The categories for this desktop entry do not contain any Main Categories, only Additional Categories. Additional Categories should only be used on conjunction with one or more Main Categories.
The desktop-file-validate tool in the desktop-file-utils package is useful for checking the syntax of desktop entries.
Please refer to https://specifications.freedesktop.org/menu-spec/latest/apa.html for details.