qBittorrent.conf related question

1: MainWindowLastDir=/xxx/xxx/xxx
The last path you chose in addFileDialog (File > add Torrent...) so that qBittorrent remembers it and uses this path as a default next time

2: ported_to_new_savepath_system=true
In v2.3.x, we truncate the root folder of multi-file torrents and this root folder is appended to the torrent save path instead. This is more similar to uTorrent and it makes it easier to rename or remove the root folder. This boolean variable is useful for forward compatibility reasons. If this variable is false, then qBittorrent knows the user upgraded from qBittorrent <= v2.2.x to qbittorrent >= v2.3.x and will append the torrent root folders to their save path so that the user does not notice the change for his existing torrents.

3: v1_4_x_torrent_imported=true
It can probably be removed by now. But basically it is similar to the previous but for v1.4.x update. I use to keep torrents configuration in separate files (with different file extensions), just near their .torrent in BTBackup. in v1.4.x, I centralized all this in a single config file (qBittorrent-resume.conf).

4: Downloads\UseIncompleteExtension=true
With libtorrent v0.15.x, you can ask qBittorrent to append a ".!qb" file extension to incomplete files. e.g. House_S01e01_.avi.!qb

Sorry, I forgot about this question because I am very busy recently (Moved to Finland and started working for Nokia).