See here for examples:
bsky.app/…/unitedkingdom.feddit.uk.ap.brid.gy
retrolemmy.com/post/31790836/17287584
There is still more testing and development needed, check the issue for more details.
In theory it should work, assuming that Bridgyfed federates the mention to Lemmy. Someone with a Bluesky account would have to test it.
@nutomic @julian that post is now deleted as it was refered to as spam-post in response. In any case, by receiving responses from lemmy, that post served its purpose. This is the notification the bluesky user received, because obviously the people responding from Lemmy do not have their accounts bridged