Accessing the saved link

First off love the plugin, works great.

I’m quite a novice so forgive me but how would I grab the external url so that I could run
update_post_meta( $post_ID, _nelioefi_url(), $externalurl );

I tried a number of things on my own but failed. Any help would be appreciated.

https://ww.wp.xz.cn/plugins/qqworld-auto-save-images/