Sieve is a powerful and much appreciated feature, but trying to implement complex filtering rules on a live mailbox is risky -- especially when you mix in the expire extension.

There is already an open request for better debugging support in the UI (see below), but I realize that might be a lot of work for the few of us that need it.

It would be great if Protonmail could release the source for their extensions. This could be used with dovecot's pigeonhole code, so that we could leverage the already existing sieve-test tool.

I already use this for testing my sieve scripts, but I have to strip out all of the stuff that is specific to protonmail for the test, and that makes doing that testing and troubleshooting substantially less effective.

Support for ManageSieve (also requested separately) would also be welcome.

Related:
https://protonmail.uservoice.com/forums/284483-proton-mail/suggestions/49342280-sieve-script-debugging-testing-support#comments
https://protonmail.uservoice.com/forums/284483-proton-mail/suggestions/42076033-remote-sieve-management-managesieve-rfc-5804