A colleague was working with a list of mine, selected some things and tried to copy. Right-mouse, and no Copy in the menu. Every windows program has Copy.
Aside: only Chrome or desktop allows the right-mouse. Edge, Firefox give you the browser context menu. In place of that, consider the hamburger menu.
It appears Ctrl-C, Ctrl-X, and Ctrl-V work for copy/cut/paste, though they are not listed in the keymap.
(Slightly surprising (but sometimes useful), Ctrl-C only copies the expanded items, not the entire tree if it is collapsed. Less usefully, Ctrl-X Cut also does this, which makes a terrible way to lose a whole lot of data when the paste fails to paste the rest of the stuff.)
Anyway, please add these 3 to the hamburger menu.