Basically this extension aims to off-load all file writing to a background “thread”, so that the Firefox user interface stays more snappy, and to avoid certain undesired stuff.
For more information about the tech-reasoning and source code, please consult the github page.
The extensions is experimental and only works with DownThemAll! trunk and Firefox 4/5 (32bit) on Windows right now.
Version 0.4alpha fixes some issues, including a very minor memory leak, and also switches from Win32 API use to NSPR, so that Mac/Linux versions are now within the reach.
(Existing users should be offered an automatic update)
PS:
The release is now signed by me (Nils Maier)
Interested developers please note (shameless plug): Not signed using signtool, but xpisign.py