Install this extension once in the same Chrome profile you use for Jobreach. After that, Find posts opens LinkedIn in your Chrome, reads search posts, and returns to Jobreach automatically. Your LinkedIn password and cookies stay in Chrome.
You do not upload a file to Jobreach. Chrome asks you to approve the extension installation once.
chrome://extensions in Chrome, turn on Developer mode, and click Load unpacked.manifest.json. This adds the extension to Chrome; it does not upload anything to the website.