Better make that all the popular non-ext4 filesystems, 2 of which are default filesystems on the 2 major Linux-distributions out there (Red hat & Ubuntu).
What on earth were they thinking?
Including sane defaults, like encryped home directories using encryptfs on ext4.
Did they have to do hoop jumping with potential security ramifications to support those? Is Dropbox on Linux running entirely within the user account or is there a system level component of it with communication to a user level component? If the latter, I could see potential areas that could at least be probed for potential vulnerabilities.
> Better make that all the popular non-ext4 filesystems...
Fair.
I'm sure they knew their numbers exactly. Probably are very few Dropbox users on Linux.
Symlinks work in MacOS too. They're only creatable from the command line (by default) but they work just like they do in Linux.
MS-Windows has them too. You need to use cmd.exe to make them. I use symlinks to keep my configuration files synced in my Nextcloud directory.
Symlinks agent common on Windows, though, as they require administrator access/elevation to create. Junction points are more common.