The founders umbrella doesn't have a season for when it was released : r/FortNiteBR
Fortnite Founder's Umbrella Glider - Pro Game Guides
Fortnite: How to get the golden umbrella - Metabomb
טוויטר \ Fortnite News | LootLake.net בטוויטר: "A player was seen using the golden Umbrella during the ESL Katowice Royale, possibly hinting at its addition to the game in the near future #
I figured that i would make a Tomatohead umbrella because the founders umbrella is a durr burger umbrella so i made a Tomatohead umbrella. : r/FortNiteBR
Fortnite new Victory Umbrella: The latest Victory Umbrella in this Fortnite season | Eurogamer.net