Lemma 8.5.6. Let $\mathcal{C}$ be a category. The $2$-category of stacks in groupoids over $\mathcal{C}$ has 2-fibre products, and they are described as in Categories, Lemma 4.32.3.

Proof. This is clear from Categories, Lemma 4.35.7 and Lemmas 8.5.2 and 8.4.6. $\square$

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