Atiyah sequence and gauge transformations of a principal 2-bundle over a Lie groupoid

In this paper, a notion of principal $2$-bundle over Lie groupoid has been introduced. For such $2$-bundles, we produced short exact sequence VB-groupoids, namely, the Atiyah sequence. Two notions connection structures viz. strict connections and semi-strict on arising respectively, from retraction up to natural isomorphism have We constructed class $\mathbb{G}=[G_1\rightrightarrows G_0]$-bundles given $G_0$-bundle $E_0\rightarrow X_0$ $[X_1\rightrightarrows X_0]$ with connection. An existence criterion for proper, \'etale is proposed. The action $2$-group gauge transformations category studied. Finally noted an extended symmetry connections.