I have just made a plugin called cliff.kak. It provides some very basic support for managing clients of a kak session. Using cliff.kak you can get current buffer for every client, as well as the list of clients currently displaying a buffer. There are also user hooks for listening them, and some other utilities.
cliff.kak also provides commands to “bind” a client/buffer to another, such that when the parent is closed, the child is also closed automatically. This can be used to clean temporary clients and buffers automatically.
IMO this plugin is not very widely applicable. I use it to do some really rare task (integrating with a interactive proof assistant). But it may be useful for people trying to use kakoune for some multi-window stuffs. So I’ve thrown it on Github. Hope someone would find it useful 