keymap.xml

<?xml version="1.0" encoding="UTF-8"?>
<keymap id="my_keymap">
    <layouts>
        <layout name="Windows" platform="PC"/>
        <layout name="macOS" platform="MAC"/>
        <layout name="Linux" platform="PC"/>
    </layouts>
    <actions>
        <action id="$Save">
            <description>Copy</description>
            <shortcut layout="Windows">Ctrl+S</shortcut>
            <shortcut layout="macOS">⌘ S</shortcut>
            <shortcut layout="Linux">Ctrl+S</shortcut>
        </action>
    </actions>
</keymap>