From what @istanbulin
said, Bursa is a semi-Oriental. Looking at ARS-GRIN, there are two "Bursa" accessions that resemble the Bursa you and I have seen.
PI 494150, Nicotiana tabacum L., TI 1668
PI 481863, Nicotiana tabacum L., 'Bursa', TI 1650
Neither displays a pedigree. Both came from the city of Bursa, and are probably the same variety. The original accession page is available for both of them, but provides no additional information.
So, Bursa is either a semi-Oriental, as @istanbulin
suggested, or a regional variant of the Samsun family.
But the story on Ainaro is that the general area of Timor-Leste was planted with pretty much one variety that resembles Viqueque and Liquiça, but that @Tutu
discovered this growing in a tiny tobacco patch alongside a humble, rural home. The folks there could not tell him anything about it. So I'm guessing it has just been percolating at that spot, all alone, for a long time. I would be surprised if somehow this subsistence farmer ordered some specific, Oriental seed.
But it's all a guess.