For second question, its an object URL. https://developer.mozilla.org/en-US/docs/Web/API/URL/createObjectURL_static https://developer.mozilla.org/en-US/docs/We

For second question, its an object URL. https://developer.mozilla.org/en-US/docs/Web/API/URL/createObjectURL_static https://developer.mozilla.org/en-US/docs/Web/API/URL/createO... It's a way to turn a file, or blob, into a URL usable with an image element etc.