• 「奪」 is short for 「奪誤」, which is jargon meaning Shape omissions or corruptions whilst publishing of ancient texts (抄刊古書而形成的文字脫漏或訛誤).
• 「耳」 is the classical sentence-termination modal particle, meaning that's all (罷了，而已).

This commentary describes Duàn Yùcái's presented opinion on the character 「𠦃」. The quote

古文省。_{此亦當云省多*。奪耳。}

_{*「多」 is a superfluous character here, and should be omitted as part of the interpretation.}

should be translated to

In ancient texts, this is Simplified¹._{This is also² deemed to be a simplification. It is a textual corruption which occurred through the transmission of ancient texts through the ages.}

where

1. "Simplified" is Duàn Yùcái's presented opinion for the ancient variants of 「卅」, which are joined at the bottom like this (see glyph evolution table):

   

   Duàn Yùcái's opinion is that, since 「卅」 is made of 3 「十」 side-by-side, in ancient texts the joining of the bottom in the 3 「十」 into 「丗」 means that the ancient forms are "simplifications" (省), and is a corruption from transmitted published texts (奪誤).

2. "Also" refers to Duàn Yùcái's commentary on the previous entry, 「廿」. In that entry, it is first argued that joining of the bottom in 「廿」 (instead of having them separate, like 「卄」) is a "simplification" (省) in ancient texts.

References:

• 《漢語大詞典》
• 季旭昇《說文新證》

• 「奪」 is short for 「奪誤」, which is jargon meaning Shape omissions or corruptions during publishing and transmission of ancient texts (抄刊古書而形成的文字脫漏或訛誤).
• 「耳」 is the classical sentence-termination modal particle, meaning that's all (罷了，而已).

This commentary describes Duàn Yùcái's presented opinion on the character 「𠦃」. The quote

古文省。_{此亦當云省多*。奪耳。}

_{*「多」 is a superfluous character here, and should be omitted as part of the interpretation.}

should be translated to

In ancient texts, this is Simplified¹._{This is also² deemed to be a simplification. It is a textual corruption which occurred through the transmission of ancient texts through the ages.}

where

1. "Simplified" is Duàn Yùcái's presented opinion for the ancient variants of 「卅」, which are joined at the bottom like this (see glyph evolution table):

   

   Duàn Yùcái's opinion is that, since 「卅」 is made of 3 「十」 side-by-side, in ancient texts the joining of the bottom in the 3 「十」 into 「丗」 means that the ancient forms are "simplifications" (省), and is a corruption from transmitted published texts (奪誤).

2. "Also" refers to Duàn Yùcái's commentary on the previous entry, 「廿」. In that entry, it is first argued that joining of the bottom in 「廿」 (instead of having them separate, like 「卄」) is a "simplification" (省) in ancient texts.

References:

• 《漢語大詞典》
• 季旭昇《說文新證》