As always, please read this with a gemara in front of you; it won't make much sense without it. Or you could skip to the less technical posts below, I suppose. There's a good post, just after this one, about shul dues and membership requirements.
The gemara records Rav Pappa’s practice of accepting non-Jewish Persian translators for Persian-language legal documents, meisiach l’fi tumo - speaking innocently, apparently without knowing their statements would have legal ramifications.
It is not entirely clear that these pseudo-witnesses need to be unaware of the legal ramifications. See, for example, Aruch haShulchan Yoreh Deah 69:58 on this. This has major ramifications for the credibility of a housekeeper in a kosher kitchen; see the Beit Yosef to Yoreh Deah 69 on this.
We may also require corroboration of his statements from outside sources (kishur devarim) - see an interesting analysis in Yad haMelech to Mishneh Torah Hilchot Geirushin 12:16.
The gemara here indicates that having letters traced (written over existing writing) in a Sefer Torah would be aesthetically unpleasing; it is not clear to me why this is so.
Rashi thinks that we accept the statement Levi cited because he worked so hard to get it accepted. That has interesting ramifications for styles of argumentation… (But see also Tosafot משמיה there.)
The gemara here uses the term ירך yerech to mean “back” or “outside.” This is reminscent of the term ירך המשכן, used, for example, in Bamidbar 3:29.
See Tosafot אשה on why a woman would not realize that she needs to give her husband the Get-materials.
Rashi at the top of the page (לא אפשר) is difficult for me to understand; why does the eved’s mitzvah obligation have anything to do with the prohibition against wounding him? First, we prohibit wounding anyone. Second, everyone has at least the mitzvot bnei Noach! I lump this together with Rashi from the bottom of 12a, as discussed here.
See Tosafot והא on the question of how one might use a person to write a Get even if he is not, personally, eligible to be one’s שליח proxy. The idea that וכתב is not an imperative for the husband to write it, but rather that it should be written by someone [and not necessarily the husband’s proxy], is interesting.
See Tosafot ממי on whether the Get-deliverer must be able to identify the husband and wife - and if so, why our problem is limited to blind delivery agents, specifically.
Of particular interest: The two Amoraim (sages of the later Talmudic era) who debate the issue of a blind delivery agent are Rav Yosef and Rav Sheshet - who were both blind, themselves.