Macro unbind_key 

macro_rules! unbind_key {
    (@cmd ($cmd:expr) -a, $($tail:tt)*) => { ... };
    (@cmd ($cmd:expr) -c, $($tail:tt)*) => { ... };
    (@cmd ($cmd:expr) -n, $($tail:tt)*) => { ... };
    (@cmd ($cmd:expr) -q, $($tail:tt)*) => { ... };
    (@cmd ($cmd:expr) -t $table:expr, $($tail:tt)*) => { ... };
    (@cmd ($cmd:expr) -T $key_table:expr, $($tail:tt)*) => { ... };
    (@cmd ($cmd:expr) $key:expr, $($tail:tt)*) => { ... };
    (@cmd ($cmd:expr)) => { ... };
    () => { ... };
    (($cmd:expr), $($tail:tt)*) => { ... };
    ($($tail:tt)*) => { ... };
}

Unbind the command bound to key

Manual

tmux >=3.2:

unbind-key [-anq] [-T key-table] key
(alias: unbind)

tmux >=2.4:

unbind-key [-an] [-T key-table] key
(alias: unbind)

tmux >=2.1:

unbind-key [-acn] [-t mode-table] [-T key-table] key
(alias: unbind)

tmux >=2.0:

unbind-key [-acn] [-t mode-table] key
(alias: unbind)

tmux >=1.5:

unbind-key [-acn] [-t key-table] key
(alias: unbind)

tmux >=0.8:

unbind-key key
(alias: unbind)