History is the list of chats saved on this device, in this browser. Spaces does not keep a server copy of your conversations. History is still scoped to the Space, like Knowledge and Controls — chats from one Space do not appear in another.

Saved conversations stay in this browser until you delete them or clear this site's data. They do not sync to another device or browser.
Sharing a conversation is different: that creates a separate link. See Share a conversation.
Every conversation is saved to History automatically, except temporary chats. On this device, you can reopen a thread and pick up where you left off — within the reply window described below.
As your list grows, two controls keep the useful threads within reach:
Deletion is permanent on this device — deleted conversations cannot be recovered.
Use Export history to download all your conversations at once. Use it as a backup, to keep a copy off this device, or to review your chats outside Spaces.
A saved conversation can be continued for 30 minutes after its last message. Once that window closes, start a new chat to continue the topic. The window keeps History stable and prevents answers from being built on stale context.