I'm not sure if I'm not understanding you, or you're not understanding me
I don't want to download any data. I simply want to create a link that shows up in the Ids: line of the Book Details. For example, putting 'amazon:B00338QEUG' in the Ids field will create the link Amazon.com
that shows in the Ids in Book Details. The link can be clicked on to open it up in a browser.
Per your reference to Metadata download plugins, I looked in Preferences -> Plugins for 'Metadata download plugins' but the only ones that started with Metadata were 'Metadata reader', 'Metadata source', and 'Metadata writer' and none of the plugins had 'download' in the title.
Can you tell me which plugins create the Google, Amazon.com or Worldcat.org links like in this example?:
If I can look at one for an example, I should be able to create my own. Unless they are hardcoded?
Also, are there any other Ids that currently work to create links? I couldn't find a list.