Circular nucleic acid sequences (DNA and RNA) are easier to align if they are already in a standard orientation. For circular Rep-encoding (eukaryote-infecting) ssDNA viruses, the convention is to orient sequences to the endonuclease nick site associated with rolling-circle replication. See Figure 2 from Zhao et al. 2019.
Branches of this repository include sets of sequences from GenBank converted to this standard orientation.