A head with the skin somebody wears HyperSkin

expressioncopy skin of <who> to <who>HyperSkin

Give the second player the skin the first one wears: the one they were given, or their own

copy skin of arg.1 to player

expressionskin texture of <who>HyperSkin

The skin a player who is online has on right now, as the text a head takes: 1 player head textured <value>. It is the skin they were given, or their own if they were given none. Unset if the server cannot tell

set {_texture} to skin texture of player

Guide and examples

command /twin <target:player>:
    permission: "skin.others"
    trigger:
        copy skin of arg.1 to player
        send "&7You now look like %arg.1%."

command /myhead:
    trigger:
        set {_texture} to skin texture of player
        if {_texture} is not set:
            send "&cYour skin could not be read."
            stop
        give 1 player head textured {_texture} named "&f%player.name%" to player

Syntax	Effect
`copy skin of <who> to <who>`	Give the second player the skin the first one wears: the one they were given, or their own
`skin texture of <who>`	The skin a player who is online has on right now, as the text a head takes: `1 player head textured <value>`. It is the skin they were given, or their own if they were given none. Unset if the server cannot tell

A head made with owned by shows the skin of that account, whatever the player is wearing; this is the one for the skin SkinsRestorer has put on them.
Heads with a texture need HyperScript 1.7.64 or newer, and Minecraft 1.18.1 or newer.