This apparently just came out. I think it is connected with a TV show that Se Ri is a part of, but I thought y'all would get a kick out of it:
The description reads, in a vague approximation of English: 'MAMAMOO+, to sing an OST for TV Chosun program 'The Queens'. 'The Queens’ is Korea’s first women’s golf survival program under the leadership of golf queen Pak Seri for the 'LPGA Gate Tour ticket'.' So now you know!