What this page is
Campaigns saved but not sent.
Open Compose in Linxi, then Drafts in the panel list beside it. It has its own address, /compose/drafts, so it can be bookmarked or sent to somebody directly rather than described as a series of clicks.
A look at it
A walkthrough of this screen — what is on it and what each control does — is being written. Until then the page itself is one click away.
Drafts
/compose/drafts