karabiner.xml

<?xml version="1.0"?>

<!--
Tap CAPS for ESC, hold CAPS + hjkl for Vim movement.

Open "System Preferences > Keyboard > Modifier Keys..." and change caps lock configuration to "No Action"
Use Seil to remap caps to F19 (80)
-->

<root>
  <item>
    <name>CAPS to ESC and FN</name>
    <identifier>private.caps_to_esc_and_fn</identifier>
    <autogen>
      __KeyOverlaidModifier__
      KeyCode::F19,
      KeyCode::FN,
      KeyCode::ESCAPE
    </autogen>
  </item>

  <item>
    <name>FN + hjkl to arrows</name>
    <identifier>private.hjkl_to_arrows</identifier>
    <autogen>__KeyToKey__ KeyCode::H, ModifierFlag::FN, KeyCode::CURSOR_LEFT</autogen>
    <autogen>__KeyToKey__ KeyCode::J, ModifierFlag::FN, KeyCode::CURSOR_DOWN</autogen>
    <autogen>__KeyToKey__ KeyCode::K, ModifierFlag::FN, KeyCode::CURSOR_UP</autogen>
    <autogen>__KeyToKey__ KeyCode::L, ModifierFlag::FN, KeyCode::CURSOR_RIGHT</autogen>
  </item>
</root>