First, Grainsberry is a typo; it was "negro Flora vs. Joseph Graisberry" per one source, and "negro Flora v. Graisberry's Executors" per another, and "Negress Flora v. Joseph Graisberry" from a third.
Second, based on review of what I can see, the case was petitioned by Flora in 1795 (with William Rawle as one of her counsels) with the view of establishing that slavery was incompatible with Pennsylvania's constitution. The details of the case, as disclosed in these sources, was about Flora's status as a slave in light of Pennsylvania's own state constitution.
From Legal Miscellany: "The High Court of Errors and Appeals and Negro Suffrage" —
[...]
From Cory James Young's doctorate dissertation "FOR LIFE OR OTHERWISE: ABOLITION AND SLAVERY IN SOUTH CENTRAL PENNSYLVANIA, 1780-1847" —
(Of particular note, per the index of slavery cases in the PA Supreme Court included with this dissertation, "Negro Flora v. Joseph Graisberry" was not reported; as such, there does not seem to be an extant copy of the actual court case and judicial opinions in question.)
From Mary Stoughton Locke's 1901 book " Anti-slavery in America from the Introduction of African Slaves to the Prohibition of the Slave Trade (1619-1808)"—
And lastly, from the Pennsylvania Magazine of History and Biography (Volume 36, No. 2, published in 1912)—
All of these sources cited point to Rawle's argument being rejected not because of his arguments regarding "natural born citizenship", but rather that the very status of "slave" was not inconsistent with Pennsylvania's own constitution. In fact, the matter of who is and is not a "natural born citizen" is not mentioned even once.
Thus, I must ask: what evidence do you have supporting your repeated contention that the Flora v. Graisberry case can be construed as a rejection of the common law understanding of "natural born citizen"?
One more source, that was referenced by Mary Stoughton Locke: "A sketch of the laws relating to slavery in the several states of the United States of America", by George M. Stroud—
On page 143, mention is made of how in Pennsylvania, "the birth place of efficient hostility to negro bondage, the highest judicial tribunal of the state, has pronounced as the result of its solemn deliberation on a similar article of her constitution, that slavery was not inconsistent with it." The corresponding footnote follows, which spills over to page 144:
On various previous threads, you've stated the following (bold is emphasis mine):
Etcetera.
If the details of this case are not on any surviving books of reports, and the only declaration from the Pennsylvania court can be paraphrased as 'slavery is not outlawed by Pennsylvania's constitution' (with no commentary regarding citizenship by birth or otherwise), how can you justify any of the claims you've made?
I said when I first started posting it that i'm not sure if I was spelling it right because it had been awhile since I had need to reference it. The case had become increasingly difficult for me to find, so I contented myself with the fact that if someone went to the trouble of looking it up, they could simply point out that I didn't spell it right, and now here we are! :)
All of these sources cited point to Rawle's argument being rejected not because of his arguments regarding "natural born citizenship", but rather that the very status of "slave" was not inconsistent with Pennsylvania's own constitution. In fact, the matter of who is and is not a "natural born citizen" is not mentioned even once.
Irrelevant. Rawle was trying to argue slaves were "born here" and were therefore "citizens", because this is the English law rule. Since Rawle appears to be the man most responsible for spreading the idea that English law governs American Citizenship, his acts and motivations are important in understanding why he spread something he knew to be false.
He was doing it for what he saw as a good reason.
Thus, I must ask: what evidence do you have supporting your repeated contention that the Flora v. Graisberry case can be construed as a rejection of the common law understanding of "natural born citizen"?
Because it is a virtual certainty that Rawle made the same arguments in 1803 that he made decades later, and for the same reason. He was trying to abolish slavery by making slaves into citizens.
I have read a lot about Rawle around a decade ago. If you want a better understanding of him, you should read more about his role in the Pennsylvania Abolition Society.