Here a two links to an interesting paper from the Gain of function guy who worked with Batwoman:
https://www.researchgate.net/publication/11091803_Systematic_Assembly_of_a_Full-Length_Infectious_cDNA_of_Mouse_Hepatitis_Virus_Strain_A59

https://jvi.asm.org/content/76/21/11065
Systematic Assembly of a Full-Length Infectious cDNA of Mouse Hepatitis Virus Strain A59
Boyd Yount, Mark R. Denison, Susan R. Weiss, Ralph S. Baric
DOI: 10.1128/JVI.76.21.11065-11078.2002
“A novel method was developed to assemble a full-length infectious cDNA of the group II coronavirus mouse hepatitis virus strain A59 (MHV-A59). Seven contiguous cDNA clones that spanned the 31.5-kb MHV genome were isolated. The ends of the cDNAs were engineered with unique junctions and assembled with only the adjacent cDNA sub-clones, resulting in an intact MHV-A59 cDNA construct of ?31.5 kb in length. The interconnecting restriction site junctions that are located at the ends of each cDNA are systematically removed during the assembly of the complete full-length cDNA product”
and so on and so forth as Dr Marc Faber would say.
(“and zo on and zo forthz”).