rabbis - Who wrote the anonymous explanations of Rashi printed within the text of Rashi?

Who wrote the anonymous explanations of Rashi printed within the text of Rashi? Sometimes when reading Rashi's commentary on the Torah one finds comments in parentheses that say things such as:

• ס"א, (another text of Rashi, = ספר אחר) or גי' רא"ם (the version of the Mizrachi, = גירסת רבינו אליהו מזרחי)


• A brief explanation of Rashi ending in וק"ל (and easy to understand, =וקל להבין) or ודו"ק

It seems remarkable that all of these comments are retained in most editions of Rashi (HaMa'or edition being a notable exception). For example, in Rashi to Shemos 22:22, the same gloss is contained in these many, many, many, many, many, many editions.

Who wrote these? (He obviously lived after the time of the Mizrachi, who lived in the fifteenth and sixteenth century.) It's a little unusual to give over a Dvar Torah in the name of Reb Anonymous.

Answer

According to Avraham Grossman, in an article published by Encyclopedia Judaica ("Rashi"), there is more than one source for these various parenthetical notations.

Some of them were composed by Rashi's students and some were composed by other scholars, but all were "later interpolated into the text by copyists". They can be identified by aid of manuscripts, "in which [they] are written between the lines" and singled out as an addition to the text. Obviously, it would be impossible to name those copyists, and a close study of the manuscripts will only indicate to you which publishing houses were responsible for including them, but not who was their author.

Such a study was undertaken in the final quarter of the 19th century by R. Avraham Berliner, in an attempt to ascertain the original (or nearly original) version of Rashi's commentary (source). It was his Rashi al-haTorah (Frankfurt, 1905) that the editors of Miqraot Gedolot (Hamaor: Jerusalem, 1990) relied upon for their publication (vol. I, page x of the introduction), although they admit to having made minor changes and of having added additional references themselves.

Long story short: unless you want to check R' Berliner's version against the extant manuscripts, you're unlikely to ever put a name to a parenthetical remark that was later copied into the text, and even if you do check through all of the different versions, such specific attribution will remain strictly speculative. My advice: get used to quoting Reb Anonymous.