Fortbyte 77 has the challenge “Found within a track side taco shop”. The Taco shop is located in the desert at the race track and the taco shop with fortbyte 77 is directly next to the track on the left side.
Fortbyte #6 | Yay! Emote at an ice cream shop in the desert (Season 9 Fortnite)
Fortbyte #7 | Use CUDDLE UP Emoticon inside a Rocky Umbrella Location (Season 9 Fortnite)
Fortbyte #8 | Found within Junk Junction (Fortnite Season 9 Fortbyte Locations)