The sieve-manage.el library contains low-level functionality for talking to a server with the managesieve protocol.
A number of user-visible variables exist, which all can be customized
sieve group (M-x customize-group RET sieve RET):
nil, should be a string naming a buffer where a protocol trace is dumped (for debugging purposes).
The API functions include:
nilif the server has room for a script of given size.