If i have page with title "foo" and url http://bar.com, when i search bar, i see the foo entry in my results, this is correct but since i don't see what am i matching i guess why the page is there at all. Now imagine a common user with some thousands pages, originally we introduced the underline matching text exactly because users were guessing where results were coming from. It could bring to miscomprehensions. Still just adding the url on the right will make "switch to tab" label hardly noticeable.

Per policy at https://wiki.mozilla.org/Bug_Triage/Projects/Bug_Handling/Bug_Husbandry#Inactive_Bugs. If this bug is not an enhancement request or a bug not present in a supported release of Firefox, then it may be reopened.