Rename File Extension on Upload

{
    "update_url": "https:\/\/clients2.google.com\/service\/update2\/crx",
    "manifest_version": 3,
    "name": "Rename File Extension on Upload",
    "version": "1.0",
    "description": "Changes specific file extensions to .txt before upload on user-approved sites.",
    "permissions": [
        "scripting",
        "storage",
        "tabs"
    ],
    "optional_permissions": [],
    "optional_host_permissions": [
        "https:\/\/*\/*",
        "http:\/\/*\/*"
    ],
    "options_ui": {
        "page": "options.html",
        "open_in_tab": true
    },
    "action": {
        "default_popup": "popup.html",
        "default_icon": {
            "48": "icon48.png"
        }
    },
    "icons": {
        "48": "icon48.png",
        "128": "icon128.png"
    }
}