Pretty sure most of you already know this but for those who don't: you have two clipboards in Linux. One is the traditional clipboard where you copy with control c and paste with control v. The other one is when you highlight text and use the mouse middle click to paste text.
More details here.
Is this applicable for Wayland as well? That link makes several references to X and its ecosystem of tools.
If I understand it correctly, Wayland only specifies a single clipboard but no primary. But most (all?) wayland compositors implement an additional protocol that's also supported by the toolkits (gtk, qt, …) and programs like wl-clipboard.
So yes, wayland also has clipboard + primary. But no secondary, as far as I found. Though I never used secondary on X anyway.