Shortcuts around cut/paste were changed because the floating selection is on the way out, The default "paste" is now pasting to a new layer, and if you check this forum's history, the old behavior was very confusing for new comers.
As far as my memory goes, Ctrl-S has always been File > Save. On my 3.x, Shift-S is still for the Scale tool, the Shear tool is Shift-H. And Ctrl-T shows/hide the selection ("marching ants") as it always did. As far as I can tell the translated versions use the same shortcuts as English, even if they are less mnemonic (the Scale tool ("Echelle" in French) is still on Shift-S and not on Shift-E).
If you are upgrading from 2.8 directly to 3.x, you are in for more surprises
As far as my memory goes, Ctrl-S has always been File > Save. On my 3.x, Shift-S is still for the Scale tool, the Shear tool is Shift-H. And Ctrl-T shows/hide the selection ("marching ants") as it always did. As far as I can tell the translated versions use the same shortcuts as English, even if they are less mnemonic (the Scale tool ("Echelle" in French) is still on Shift-S and not on Shift-E).
If you are upgrading from 2.8 directly to 3.x, you are in for more surprises