Where is the list of sidebar's favourites stored in macOS Sierra?
I tried to delete
~/Library/Preferences/com.applde.sidebarlist.plist - almost all preferences are reset except list of favourites - it remains
Thanks to @TonyWilliams for the starting point and after a brief research I realized that requested sidebar's favourites are stored actually in directory
~/Library/Application Support/com.apple.sharedfilelist/, the file
com.apple.LSSharedFileList.FavoriteItems.sfl among other files which are responsible for other sidebar sections. But those files are not available for easy editing.
Starting from OSX El Capitan and newer versions there is a command-line tool sfltool availabe to make some operations with that files, such as add an item. But this tools doesn't have ability to remove items (the root of my problem which causes to this research) and I found another good tool on GitHub called mysides which allows to remove items as well.
The sidebar's favourites are managed by
sharedfilelistd which is an XPC service, don't try to manipulate it manually. This way lies pain and suffering.