“This canvas” means this canvas
When you open the “+” to pick a reference, the “This canvas” tab used to include things you couldn't actually see on the canvas: copies left behind when you picked from another canvas, outputs replaced by a re-generation, leftovers from nodes you had deleted.
It now lists only what is really on this canvas: if the node is there, so is the asset; delete the node and it disappears immediately. “Other canvases” follows the same rule.
“Generation history” is unchanged — that tab is the generation record for this canvas, including output from nodes you later deleted. That's where to look for older images.
Cards have names now
Asset cards used to be titled “Untitled” almost every time (generated images have no filename). They now show the name of the node they belong to — the title you gave that node, and renaming it updates the list. Especially handy when picking from another canvas: you can tell at a glance which node an image came from.
Rejected references explain themselves
When a reference can't be used, the message now says which kind of problem it is and what to change — for example that the model does not take reference audio, that start/end-frame mode doesn't use reference video or audio, or that a referenced asset no longer exists.