Thanks for reply!!
I think that video is about Select all with same variant.
In Quick Action that i can know Select all with same variant and Select all matching layers are using same keyboard shortcuts. So still mystery what does matching by
“Select all matching layers” only works for layers within variants of the same component set. Whereas the “Select all with…” functions will select all layers on the page.
Can confirm tank666’s response, “Select all matching layers” only applies to variant editing. Screenshot attached for those who prefer still images over videos (such as myself).
“Select all matching layers” will be disabled when anything but a layer within a component set is selected, and the Ctrl+Alt+A shortcut will only work for this command and not other “Select all with…” commands.
Will agree that the name is pretty confusing though. I always forget what it does whenever I see it in the Quick Action search… Could be nice if they included a tiny bit of context there like in the Keyboard Shortcuts panel