Caps Lock as Escape *and* Control key.

caps_lock_as_esc_and_ctrl_key

$ tree ~/.xkb

.xkb
├── keymap
│   └── default
└── symbols
    └── capslock


$ xkbcomp -I${HOME}/.xkb ${HOME}/.xkb/keymap/default $DISPLAY

keymap_default

default xkb_keymap "default" {
    xkb_keycodes  { include "evdev+aliases(qwerty)" };
    xkb_types     { include "complete" };
    xkb_compat    { include "complete" };
    xkb_symbols   {
        include "pc+us(altgr-intl)+inet(evdev)+capslock(capsescape)"
    };
};

symbols_capslock

// Replace Caps Lock with Escape + Control
partial hidden modifier_keys
xkb_symbols "capsescape" {
    replace key <CAPS> {
        type[Group1] = "ONE_LEVEL",
        symbols[Group1] = [ Escape ],
        actions[Group1] = [ SetMods(modifiers=Control) ]
    };
};