Scavenger Hunt: Bear School Gear Upgrade Diagrams - Part 1 is a Skellige side quest / treasure hunt with suggested level 16.

The Scavenger Hunt quests can be picked up from purchasing "maps" from vendors/blacksmiths/armorers, or just buy heading to the locations themselves to loot the treasures.

This particular quest can be picked up from Oxenfurt's armorer and purchasing and reading "Ibraham Savi's First Map". Quest only becomes available after unlocking Skellige as a possible destination.

Enhanced Ursine Silver Sword

Triangulated between Giant's Toes, Yustianna's Grotto, and Kaer Gelen is another set of ruins.

Go through the main arch and into the door where you will have to take out some level 21 Alghoul. Turn left and head down the hall until you reach a larger area with more Alghoul to fight.

The back of this cavern is where you can find the chest and the silver sword diagram.

Enhanced Ursine Armor

Go to the south-east coast on the main island in Skellige to the cave at the Grotto signpost.

Hug the right wall to avoid swimming and go through the hallway to a large open cavernous area where you should turn left and then right into the next corridor and open area. 

Defeat the level 26 enemies and turn left to a rock near the center of the area. Here you will find the chest containing the diagram for enhanced ursine armor.

Enhanced Ursine Boots

Go down the road from Wild Shore and then head East to find a cave in the side of the mountain.

Head straight in and down the long hall to defeat the level 16 trolls in the open area. Then go to the pointy section beyond the campfire and claim the chest.