Можно ли Deskzille как-то обяснть, что в Bugzille записи хранятся в KOI-8, а показывать их надо в ср1251?

It is not currently possible.

We're working on supporting national charsets and one of the future releases will contain an option for setting a character set on a connection, similar to View - Encoding menu item in Internet Explorer.

It looks like this is Bugzilla's behavior, which does not return correct charset. I think it is possible to hack Bugzilla so that it reports correct charset - I'm going to investigate this possibility asap. I'll report on this topic then.

Best regards,
Igor