Finally the add-on was revived! Rated 5 out of 5 stars
A similar functionality once was removed from the browser (in the Age of Idiocy, that Firefox suffered much from). And that's why Extended Link Properties appeared (and it got very popular, just as a proof that Mozilla's management took a wrong decision to remove that functionality from the browser).
I don't know the reasons why that add-on was disabled on AMO, but it is very nice, that it has now been revived and is being developed!