Written between 1276 and 1285, L is not an autograph, but rather a copy with copyists errors. Bubers edition contains many inaccuracies and misunderstanding of the text, a number of which Zipor discusses in his introduction. Two other partial manuscripts of RZ are known. The expanded edition in L uses Rashis commentary as a base, blending into it materials from RZ, as well as from other Talmudic and midrashic sources. In the course of blending, L adapts and abbreviates these sources.
L is significant for several reasons.
First, since it copies Rashis commentary almost verbatim, it provides significant testimony to changes in the text of Rashis Ruth commentary, and sheds new light on several of Rashis comments. Second, L contains several sections of midrash unknown to us from other sources. Third, it uses the technique, which seems to have been generally accepted, in adapting other sources and integrating them into Rashis commentary. Fourth, it serves as an important textual witness to RZ, as indicated in Zipors introduction, and may be much help in reconstructing it. Rafeld shows that this rule was common with Alfasi, with the school of R.Meir of Rothenberg, and in Piskei Ha-Rosh of R. Asher.