Can `content_scripts` detect if a `command` is set?

My extension currently uses the [esc] key to perform an action.

This is done in the content-script, using addEventListener('keydown').

I'd like the user to be able to choose a different shortcut.

I've updated to Manifest V3, and added a new "commands" key, i.e.

{
    ...
    "manifest_version": 3,
    "background": {
            "service_worker": "background.js"
        },
    "content_scripts": [ {
            "js": [ "screenshot.js" ],
            "matches": [ "http://*/*", "https://*/*" ]
         }],
    "commands": {
        "stop-animations": {
            "description": "Stop Animations"
        }
    }
}

I've updated background.js to use chrome.commands.onCommand, and this works well.

But, how can I get my content-script to determine if the user has set their own shortcut?

Because I should not listen to the 'keydown' event to check if they have pressed the [esc] key.

I've tried using chrome.commands.getAll(), but this method is only available at install time.

A partial option would be to use something like browser.storage to set a simple boolean "custom-command-set" to true whenever onCommand is used, but I cannot think of a way to switch it off again if the user deletes the shortcut command (i.e. they want to go back to using the [esc] key).

At the moment I don't have a toolbar icon (action default_popup), or any other UI, and I'd prefer to not add one just to provide a custom way to set the shortcut.

Content scripts can't call chrome.commands.getAll() directly, so they need to send a message to the service worker. The SW calls chrome.commands.getAll() and sends the result back to the content script.

manifest.json

{
    "manifest_version": 3,
    "name": "chrome.commands.getAll",
    "version": "1.0.0",
    "background": {
          "service_worker": "background.js"
    },
    "content_scripts": [
        {
            "js": [ "content_script.js" ],
            "matches": [ "*://*/*" ]
        }
    ],
    "commands": {
        "test": {
            "description": "Test"
        }
    },
    "permissions": ["commands"]
}

background.js

function commands_on_command(command) {
    console.log("on_command", command);
}

function runtime_on_message(message, sender, sendResponse) {
    if (message == "get_all_commands") {
        chrome.commands.getAll()
        .then(commands => {
            console.log("background.js", "runtime_on_message", commands);
            sendResponse(commands);
        });
        return true; // https://developer.chrome.com/docs/extensions/mv3/messaging/#simple
    }
    else {
        console.log("background.js", "runtime_on_message", "unknown command");
        sendResponse("unknown command");
    }
}

chrome.commands.onCommand.addListener(commands_on_command);
chrome.runtime.onMessage.addListener(runtime_on_message);

content_script.js

(async () => {
    let response = await chrome.runtime.sendMessage("get_all_commands");
    console.log("content_script.js", response);
})();