Usage of native GUI controls for web content rendering allows fingerprinting
TBB is using native OS GUI controls in Web content (scrollbars, check boxes, comba boxes, ...).
If a user has customized the OS UI settings (e.g. scrollbar size) or installed a custom OS theme, a web page can detect the different control metrics.
This applies at least on Windows. On Linux, TBB appears to ignore the GTK OS config.
To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information