You gain the following benefits.

Ability Score Increase. Increase your Strength or Dexterity score by 1, to a maximum of 20. You cannot benefit from this again if you already have Weapon Fighting Technique.

Hew. Immediately after you score a Critical Hit with a Melee weapon or reduce a creature to 0 Hit Points with one, you can make one attack with the same weapon as a Bonus Action. You are still able to use a Bonus Action that enhances the same weapon if it is in conjunction with your Melee weapon attack.

Critical Technique. When you hit a creature with a weapon that you are proficient in with weapon mastery, you can choose one of the following: to have Advantage on attacks rolls against that creature made with the same weapon until the beginning of your next turn, or that creature has Disadvantage on attack rolls until the start of your next turn

Heavy Weapon Mastery. When you hit a creature with a weapon that you are proficient in with weapon mastery, as part of the Attack action on your turn, you can cause the weapon to deal extra damage to the target. The extra damage equals your half of your Proficiency Bonus, rounded down. If you have Weapon Fighting Technique this bonus is increased to your full Proficiency Bonus.