The fundamental groupoid as a terminal costack (Q897460)

The paper starts with the observation that, for a locally connected topological space \(X\), \(\pi_0(-)\) is a terminal cosheaf on \(X\). The main result is that, for a good topological space \(X\), \(\pi_1(-)\) is a 2-terminal costack on \(X\). Costacks take values in groupoids and they form a 2-category. The key fact is that some colimits in this 2-category are equivalent to 2-colimits.