It was already previously possible to navigate through Kube by moving the keyboard focus using tab and arrow keys, however that is neither fast nor efficient. To be able to really blaze through your Inbox we naturally require VIM style keybindings. To move through the UI we want to be able to go through folders, threads and mails using a single key press, without worrying where the focus currently is.
The Conversation view thus sports the following hotkeys:
Jump to next thread: j
Jump to previous thread: k
Jump to next message: n
Jump to previous message: p
Jump to next folder: f, n
Jump to previous folder: f, n
Compose new message: c
Reply to the currently focused message: r
Delete the currently focused message: d
Mark the currently focused message as important: i
Mark the currently focused message as unread: u
Scroll the conversation up/down: Arrow keys
Show a help popup with these hotkeys: ?
These shortcuts are usable from anywhere within the Conversation view, so you can blaze through your Inbox in no time.