They’re under a section called “novels,” but the text makes it pretty clear:

The first book of the series, All Systems Red, was published in May 2017. A sequel, Artificial Condition, was released on May 8, 2018,[1] followed by Rogue Protocol on August 7, 2018.[2][3] The next installment, Exit Strategy, was released on October 2, 2018.[4] Wells noted in 2017 that the four novellas “do have an overarching story, with the fourth one bringing the arc to a conclusion.”[1] A full-length Murderbot novel , Network Effect, was released on May 5, 2020.[5][6][7]