Advanced
Option	Kind	Default Value	Description
dht-enabled	Boolean	true
encryption	Number	1	0 = Off, 1 = Preferred, 2 = Forced
lazy-bitfield-enabled	Boolean	true
open-file-limit	Number	32
peer-socket-tos	Number	0
pex-enabled	Boolean	true
rename-partial-files	Boolean	true	Sets wether default Transmission should postfix partially downloaded files with ".part"
preallocation	Number	1	0 = Off, 1 = Fast, 2 = Full (slower but reduces disk fragmentation
umask	Number	18	Sets transmission's file mode creation mask. See ​the umask(2) manpage for more information. Users who want their saved torrents to be world-writable may want to set this value to 0. Bear in mind that the json markup language only accepts numbers in base 10, so the standard umask(2) octal notation "022" is written in settings.json as 18.
Bandwidth
Option	Kind	Default Value	Description
speed-limit-down	Number (KB/s)	100
speed-limit-down-enabled	Boolean	false
speed-limit-up	Number (KB/s)	100
speed-limit-up-enabled	Boolean	false
alt-speed-enabled	Boolean	false	aka 'Turtle Mode'. Clicking the "Turtle" in the gui when the scheduler is enabled, will only temporarily remove the scheduled limit until the next cycle.
alt-speed-up	Number (KB/s)	50
alt-speed-down	Number (KB/s)	50