An option that allows you to import or export items from the chest you are standing on.

Description of what I mean:

If we want to export the entire page from the client chest while standing on the chest, just click the button on this page.

If we want to import items to the client chest while standing on the chest, we open the page (a new page or a page with items) and then click the import button.

Importing and exporting should maintain the order and location of items in a single or double chest.

It's probably better to use a command like /clientchest (import | export) <page number | page name> [top | bottom], where it uses what you're looking at, in case it isn't easy to stand on the chest of interest (eg. two block high ceiling), but the concept sounds useful.

This has a similar vibe to a really old idea I had when first making this mod: /pack and /unpack, which would save and retrieve your inventory to and from a container (kind of like saved hotbars, but for the entire inventory). Maybe I could combine both of these into some sort of /transfer command, which would move items between the client chest, your inventory, containers in your inventory, and containers in the world.