I've noticed recently Facebook has started using URLs which seem to include encoded information.

For example, this URL to Vice: https://www.facebook.com/VICE/posts/pfbid02XdVziPTwhmPU9XzBq...

It's a pretty URL with some kind of hash at the end beginning with "pfbid."

Whereas they used to look like basic sharded URLs: https://www.facebook.com/random.username/posts/1020832750980...

Is this for more targeted tracking on posts and links being shared, a new sharding scheme, a combination of both, or something else entirely?

Appreciate any insights the community can provide.