Is it possible to make carts private? It could help developers to make multicart games, the secondary carts could be private

As far as I know, carts aren't listed in Splore or anywhere else unless they're in a BBS post. So they're effectively private, as long as they aren't in a post and you don't tell anyone the ID.

I could use this too for experimentation.

Pico-8 Cloud Storage.

Suggest future Pico-8 allow the possibility to upload a cartridge from the Pico-8 system itself. Maybe allow each registered user 1mb to 2mb of personal cloud storage space specifically for Pico-8 work.

This space is private though and can only be accessed by the owner w optional password. Making use of IP protection additionally if so desired for greater protection.

For instance, you could type:

SAVE @EN2389,"QSDKFH"

To save your work to your personal Pico-8 cloud and optionally password protect it.

Then later

LOAD @EN2389,"QSDKFH"

To load from your personal cloud space Entropy model 2389 using the password you set for it, "QSDKFH."

You could view your cloud via:

DIR("@")

This of course would require an online connection.

. . .

Simpler than this though a new category could be created called PRIVATE that only the owner of the post can see - where you can write whatever you want. Experimental carts, notes, and information.