The quotes are there to indicate that the free will is there but only as a convenient abstraction.
"The idea of the self over time [...] is the property of phenomenal selfhood that plays the most important role in creating the fictional self and the first person perspective. Metzinger defines the first person perspective as the “existence of single coherent and temporally stable model of reality which is representationally centered around or on a single coherent and temporally stable phenomenal subject”."
Free will in this sense is used to model reality in the form of subjective experience, part of which includes ownership of self. In other words we experience free will as a property of our model of reality, but it does not exist outside this abstraction. Objectively we are causally determined, subjectively we experience free will as part of the modeling process by the brain to create predictions about how it should respond to external stimuli.
Self is an abstraction inside a simulation, it does not map onto reality directly. But since our subjective reality is the simulation, we will always experience ourselves as having free will barring a brain disorder, such as the ones mentioned in the wiki link: "Disorders of the self model are implicated in several disorders including schizophrenia, autism, and depersonalization."