karabiner

rules

            "complex_modifications": {
                "parameters": {
                    "basic.simultaneous_threshold_milliseconds": 50,
                    "basic.to_delayed_action_delay_milliseconds": 500,
                    "basic.to_if_alone_timeout_milliseconds": 1000,
                    "basic.to_if_held_down_threshold_milliseconds": 400,
                    "mouse_motion_to_scroll.speed": 100
                },
                "rules": [
                    {
                        "description": "long left_shift to page_up / left_shift pressed alone to home",
                        "manipulators": [
                            {
                                "from": {
                                    "key_code": "left_shift",
                                    "modifiers": {
                                        "optional": [
                                            "any"
                                        ]
                                    }
                                },
                                "to": [
                                    {
                                        "key_code": "left_shift"
                                    }
                                ],
                                "to_if_alone": [
                                    {
                                        "key_code": "home"
                                    }
                                ],
                                "to_if_held_down": [
                                    {
                                        "key_code": "page_up",
                                        "halt": true
                                    }
                                ],
                                "type": "basic"
                            }
                        ]
                    },
                    {
                        "description": "long right_shift to page_down / right_shift pressed alone to end",
                        "manipulators": [
                            {
                                "from": {
                                    "key_code": "right_shift",
                                    "modifiers": {
                                        "optional": [
                                            "any"
                                        ]
                                    }
                                },
                                "to": [
                                    {
                                        "key_code": "right_shift"
                                    }
                                ],
                                "to_if_alone": [
                                    {
                                        "key_code": "end"
                                    }
                                ],
                                "to_if_held_down": [
                                    {
                                        "key_code": "page_down",
                                        "halt": true
                                    }
                                ],
                                "type": "basic"
                            }
                        ]
                    },
                    {
                        "description": "Change fn to forward delete",
                        "manipulators": [
                            {
                                "from": {
                                    "key_code": "fn"
                                },
                                "to": [
                                    {
                                        "key_code": "delete_forward"
                                    }
                                ],
                                "type": "basic"
                            }
                        ]
                    }
                ]
            },