My friend tried it. He said that he received a free sample of good (but unenhanced) kratom.
He put around a tablespoon into a small jar, with about 2 shots of vodka. Then he microwaved it for about 4-5 minutes as the vodka boiled. Then he filtered the vodka/powder through a fine-mesh strainer (or coffee filter, can't remember which) to get just vodka with the kratom extract in it.
He poured the hot vodka and extract into a large evaporating dish to let a lot of the alcohol evaporate. Once it reached room temperature, there was barely any alcohol left. He drank it all at once. Around 30 minutes later, he started feeling nice, and then that swelled into a low-grade euphoria/bliss for a few hours. It wore off with no side effects and he was completely baseline at the 5 hour mark.
He said that he had once tried eating an equivalent amount of kratom powder once but he got nausea, and he read about the hot ethanol extraction technique on the internet and there was no nausea when he drank the extract.