Maybe there is a linux specification, just that most software doesn´t follow it. Same as most software doesn´t follow Windows specifications for where placing files, or for placement and use of shared libraries. And same as in linux, with its dependencies.
But having a publisher name in the tree helps, when one has more than one software package from the same source.
One thing is how apps are organized in the menu. On Linux this is defined by XDG menu-spec: menu-spec . We can at least use their category list as a starting point (it would replace the “Applications / Demos / Games / Preferences” menus we currently have, I think?): A. Registered Categories
Another is where the files are stored on disk. This on Linux is defined by the linked filesystem hierarchy standard, but I don’t see why it is included in this discussion.
The Linux & BSD, menus group programs by their use - which is easy, even for newbies, to find what they want, & if they don’t fit a specific group, they usually go in ‘Accessories’ or ‘System’ - other main groups are - ‘Multimedia’ - ‘Office’ - ‘Games’ - ‘Development’ - ‘Graphics’ - ‘Internet’ - & sometimes, ‘Other’, if they don’t really fit in the other category of groups.
i was wondering about that too… probably a misunderstanding of the difference between directory and folder.
nevertheless… and as you also pointed out, there are standards in place and honestly, i havent seen a misplaced menu/grouped/(foldered?) item in either gnu/linux nor in haiku.