During a hangout, one SEO professional asked John Mueller about URLs in structured data markup.
Their question was: does Google crawl URLs located in structured data markup, or does Google just store the data?
John explained that for the most part, when Google looks at HTML pages, if they see something that looks like a link, they may go off and try to get the URL out as well.
If they find a link in a text file on a site, they can try and crawl that and use it. But, it’s not really a normal link. So, it’s something where John recommends if you want Google to go off and crawl that URL, then make sure that there’s an actual HTML link to that URL, with clear anchor text as well that you give some information about the destination page.
If you don’t want Google to crawl that specific URL, then maybe block it with robots.txt, or on that page, use a rel=canonical pointing to your preferred version, anything like that.
So those are the directions that John would go there. He would not blindly assume that just because it’s in structured data, that it will be found.
It might be found, it might not. John would instead focus on what you want to have happen there.
If you want to have it seen as a link, then make it a link. If you don’t want to have it crawled or indexed, then block crawling or indexing.
This is all totally up to you.
This happens at approximately the 23:20 mark in the video.