qmk_firmware/keyboards/planck/keymaps/dr0ck

This layout adds a new function layer similar to the default one from the pok3r:

/* Function
 * ,-----------------------------------------------------------------------------------.
 * | Esc  |      | Prev | Play | Next |      |      |Pg Up |  Up  |Pg Dn |Prt Sc| Del  |
 * |------+------+------+------+------+-------------+------+------+------+------+------|
 * |      |      | Vol- | Mute | Vol+ |      | Home | Left | Down |Right | End  |      |
 * |------+------+------+------+------+------|------+------+------+------+------+------|
 * |      |      |      |      |      |      |      |      |      |      |      |      |
 * |------+------+------+------+------+------+------+------+------+------+------+------|
 * |      |      |      |      |      |             |      | Home |Pg Up |Pg Dn | End  |
 * `-----------------------------------------------------------------------------------'
 */

You can acces this layer by holding the first key on the second line from the top.