[Protostome]

Bioinformatician here, BsaI and BsmBI are Type IIS restriction enzymes. Which means, they are unique in the fact that they cleave DNA at a defined distance outside of their recognition sequence.

BsaI has been used in high throughput assembly techniques such as Golden Gate assembly and Golden Braid assembly.

Golden Gate assembly is an extremely robust method for building modular genetic components. For example, one can create plasmids (circular pieces of DNA) with billions of variants of the spike proteins, each carrying a different combination of mutations. Then, those plasmids are transfected into corona viruses and incubated in a tissue culture. Now, one usually let natural selection do its thing and the most infective variants replicate in the tissue much faster and take over the population.

Having said all that, type 2s restriction sites usually are cut out during assembly so I'm not sure how having those is a good evidence for engineering. Actually, the opposite is true. Having none at all is one evidence which is very much suspicious