How to get just two items of a json like file

I'm trying to parse the Sublime Text 3 session file: **Session.sublime_session**. It consist of what look like JSON formatted stuff. Using:

cat Session.sublime_session | grep -A13 "\"file\":"

I can get easily get a list (repeated for each file) like this:

"file": "/F/myHW/check_usb_switch.sh",
	"semi_transient": false,
	"settings":
	{
			"buffer_size": 873,
			"regions":
			{
			},
			"selection":
			[
					[
							872,
							872
					]
--

How can I get a list like this:

/F/myHW/check_usb_switch.sh:872
...

(Are there other or more suitable tools for this? (E.g. **jq** etc?) --- Requested info:

# Start of file:
{
        "folder_history":
        [
        ],
        "last_version": 3176,
        "last_window_id": 9,
        "log_indexing": false,
        "settings":
        {
                "new_window_height": 912.0,
                "new_window_settings":
                {
                        "auto_complete":
                        {
                                "selected_items":
                                [
                                        [
                                                "input",
                                                "input_stream"
                                        ],
...
        },
        "windows":
        [
                {
                        "auto_complete":
                        {
                                "selected_items":
                                [
                                        [
                                                "file",
                                                "fileName"
...
                                        [
                                                "json",
                                                "json_response"
                                        ]
                                ]
                        },
                        "buffers":
                        [
                                {
                                        "file": "/F/xxxx.sh",
                                        "settings":
                                        {
                                                "buffer_size": 7040,
                                                "encoding": "UTF-8",
                                                "line_ending": "Unix"
                                        }
                                },
                                {
                                        "file": "/C/xxxx.txt",

--- Request-2:

{
                                                        "buffer": 1,
                                                        "file": "/C/Users/xxxx/Desktop/tmp/xxxx.txt",
                                                        "semi_transient": false,
                                                        "settings":
                                                        {
                                                                "buffer_size": 6529,
                                                                "regions":
                                                                {
                                                                },
                                                                "selection":
                                                                [
                                                                        [
                                                                                3569,
                                                                                3569
                                                                        ]
                                                                ],
                                                                "settings":
                                                                {
                                                                        "syntax": "Packages/Text/Plain text.tmLanguage",
                                                                        "word_wrap": false
                                                                },
                                                                "translation.x": 0.0,
                                                                "translation.y": 0.0,
                                                                "zoom_level": 1.0
                                                        },
                                                        "stack_index": 46,
                                                        "type": "text"
                                                },