It is deemed to have an RNA repair mechanism. This is suggested by analogy with other coronaviruses [1,2] and the length of its RNA of ~30k nucleotides while the upper limit for RNA without repair mechanism seems to be 10k [3]. The german wikipedia cites [4] which I found nicer to read.
[1] https://en.wikipedia.org/wiki/Coronavirus#Replication [2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4984655/ [3] https://de.wikipedia.org/wiki/Coronaviridae#Genom [4] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3127101/